diff --git a/README.md b/README.md
index 9efc0b7..6440ebf 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ $ npm install faiss-node
 ## Usage
 
 ```javascript
-const { IndexFlatL2, Index, IndexFlatIP, MetricType } = require('faiss-node');
+const { IndexFlatL2, Index, IndexFlatIP, IndexHNSW, MetricType } = require('faiss-node');
 
 const dimension = 2;
 const index = new IndexFlatL2(dimension);
@@ -80,7 +80,9 @@ const deserializedIndex = Index.fromBuffer(index_buf);
 console.log(deserializedIndex.ntotal()); // 3
 
 // Factory index
-const hnswIndex = Index.fromFactory(2, 'HNSW,Flat', MetricType.METRIC_INNER_PRODUCT);
+const hnswIndex = Index.fromFactory(2, 'HNSW32,Flat', MetricType.METRIC_INNER_PRODUCT);
+// same as:
+// const hnswIndex = new IndexHNSW(2, 32, MetricType.METRIC_INNER_PRODUCT)
 const x = [1, 0, 0, 1];
 hnswIndex.train(x);
 hnswIndex.add(x);
diff --git a/lib/index.d.ts b/lib/index.d.ts
index 0bca395..33d5d8a 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -158,4 +158,50 @@ export class IndexFlatIP extends Index {
      * @param {IndexFlatIP} otherIndex The other IndexFlatIP instance to merge from.
      */
     mergeFrom(otherIndex: IndexFlatIP): void;
+}
+
+/**
+ * IndexHNSW Index.
+ * The Hierarchical Navigable Small World indexing method is based on a graph built on the indexed vectors.
+ * @param {number} d The dimensionality of index.
+ * @param {number} m The number of neighbors used in the graph (defaults to 32).
+ * @param {number} metric Metric type (defaults to L2).
+ */
+export class IndexHNSW extends Index {
+    IndexHNSW(d?: number, m?: number, metric?: MetricType);
+    /** 
+     * Read index from a file.
+     * @param {string} fname File path to read.
+     * @return {IndexHNSW} The index read.
+     */
+    static read(fname: string): IndexHNSW;
+    /** 
+     * Read index from buffer.
+     * @param {Buffer} src Buffer to create index from.
+     * @return {IndexHNSW} The index read.
+     */
+    static fromBuffer(src: Buffer): IndexHNSW;
+    /**
+     * Merge the current index with another IndexHNSW instance.
+     * @param {IndexHNSW} otherIndex The other IndexHNSW instance to merge from.
+     */
+    mergeFrom(otherIndex: IndexHNSW): void;
+    /**
+     * The depth of exploration at add time.
+     */
+    get efConstruction(): number;
+    /**
+     * The depth of exploration at add time.
+     * @param {number} value The value to set.
+     */
+    set efConstruction(value: number);
+    /**
+     * The depth of exploration of the search.
+     */
+    get efSearch(): number;
+    /**
+     * The depth of exploration of the search.
+     * @param {number} value The value to set.
+     */
+    set efSearch(value: number);
 }
\ No newline at end of file
diff --git a/lib/index.js b/lib/index.js
index ced9f1f..02129ae 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -14,4 +14,25 @@ var MetricType;
   MetricType[MetricType["METRIC_Jaccard"] = 23] = "METRIC_Jaccard";
 })(MetricType || (faiss.MetricType = MetricType = {}));
 
+if (!('efConstruction' in faiss.IndexHNSW.prototype)) { // prevents redefinition in jest
+  Object.defineProperty(faiss.IndexHNSW.prototype, 'efConstruction', {
+    get: function () {
+      return this.getEfConstruction();
+    },
+    set: function (value) {
+      this.setEfConstruction(value);
+    }
+  });
+}
+if (!('efSearch' in faiss.IndexHNSW.prototype)) { // prevents redefinition in jest
+  Object.defineProperty(faiss.IndexHNSW.prototype, 'efSearch', {
+    get: function () {
+      return this.getEfSearch();
+    },
+    set: function (value) {
+      this.setEfSearch(value);
+    }
+  });
+}
+
 module.exports = faiss;
\ No newline at end of file
diff --git a/src/faiss.cc b/src/faiss.cc
index f32b6b7..b766853 100644
--- a/src/faiss.cc
+++ b/src/faiss.cc
@@ -9,11 +9,20 @@
 #include <faiss/index_factory.h>
 #include <faiss/MetricType.h>
 #include <faiss/impl/IDSelector.h>
+#include <faiss/IndexHNSW.h>
 
 using namespace Napi;
 using idx_t = faiss::idx_t;
 
-template <class T, typename Y>
+enum class IndexType
+{
+  Index,
+  IndexFlatL2,
+  IndexFlatIP,
+  IndexHNSW,
+};
+
+template <class T, typename Y, IndexType IT>
 class IndexBase : public Napi::ObjectWrap<T>
 {
 public:
@@ -21,7 +30,25 @@ class IndexBase : public Napi::ObjectWrap<T>
   {
     Napi::Env env = info.Env();
 
-    if (info.Length() > 0 && info[0].IsNumber())
+    if constexpr (IT == IndexType::IndexHNSW)
+    { // HNSW constructor
+      if (info.Length() > 0 && info[0].IsNumber())
+      {
+        auto n = info[0].As<Napi::Number>().Uint32Value();
+        auto m = 32;                                // faiss default
+        auto metric = faiss::MetricType::METRIC_L2; // faiss default
+        if (info.Length() > 1 && info[1].IsNumber())
+        {
+          m = info[1].As<Napi::Number>().Uint32Value();
+        }
+        if (info.Length() > 2 && info[2].IsNumber())
+        {
+          metric = static_cast<faiss::MetricType>(info[2].As<Napi::Number>().Uint32Value());
+        }
+        index_ = std::unique_ptr<faiss::IndexHNSW>(new faiss::IndexHNSW(n, m, metric));
+      }
+    }
+    else if (info.Length() > 0 && info[0].IsNumber())
     {
       auto n = info[0].As<Napi::Number>().Uint32Value();
       index_ = std::unique_ptr<Y>(new Y(n));
@@ -446,7 +473,7 @@ class IndexBase : public Napi::ObjectWrap<T>
 };
 
 // faiss::Index is abstract so IndexFlatL2 is used as fallback
-class Index : public IndexBase<Index, faiss::IndexFlatL2>
+class Index : public IndexBase<Index, faiss::IndexFlatL2, IndexType::Index>
 {
 public:
   using IndexBase::IndexBase;
@@ -481,7 +508,7 @@ class Index : public IndexBase<Index, faiss::IndexFlatL2>
   }
 };
 
-class IndexFlatL2 : public IndexBase<IndexFlatL2, faiss::IndexFlatL2>
+class IndexFlatL2 : public IndexBase<IndexFlatL2, faiss::IndexFlatL2, IndexType::IndexFlatL2>
 {
 public:
   using IndexBase::IndexBase;
@@ -515,7 +542,7 @@ class IndexFlatL2 : public IndexBase<IndexFlatL2, faiss::IndexFlatL2>
   }
 };
 
-class IndexFlatIP : public IndexBase<IndexFlatIP, faiss::IndexFlatIP>
+class IndexFlatIP : public IndexBase<IndexFlatIP, faiss::IndexFlatIP, IndexType::IndexFlatIP>
 {
 public:
   using IndexBase::IndexBase;
@@ -549,11 +576,104 @@ class IndexFlatIP : public IndexBase<IndexFlatIP, faiss::IndexFlatIP>
   }
 };
 
+class IndexHNSW : public IndexBase<IndexHNSW, faiss::IndexHNSW, IndexType::IndexHNSW>
+{
+public:
+  using IndexBase::IndexBase;
+
+  static constexpr const char *CLASS_NAME = "IndexHNSW";
+
+  Napi::Value getEfConstruction(const Napi::CallbackInfo &info)
+  {
+    auto index = dynamic_cast<faiss::IndexHNSW *>(index_.get());
+    return Napi::Number::New(info.Env(), index->hnsw.efConstruction);
+  }
+
+  Napi::Value setEfConstruction(const Napi::CallbackInfo &info)
+  {
+    Napi::Env env = info.Env();
+
+    if (info.Length() != 1)
+    {
+      Napi::Error::New(env, "Expected 1 argument, but got " + std::to_string(info.Length()) + ".")
+          .ThrowAsJavaScriptException();
+      return env.Undefined();
+    }
+    if (!info[0].IsNumber())
+    {
+      Napi::TypeError::New(env, "Invalid the first argument type, must be a Number.").ThrowAsJavaScriptException();
+      return env.Undefined();
+    }
+
+    auto index = dynamic_cast<faiss::IndexHNSW *>(index_.get());
+    index->hnsw.efConstruction = info[0].As<Napi::Number>().Int32Value();
+    return env.Undefined();
+  }
+
+  Napi::Value getEfSearch(const Napi::CallbackInfo &info)
+  {
+    auto index = dynamic_cast<faiss::IndexHNSW *>(index_.get());
+    return Napi::Number::New(info.Env(), index->hnsw.efSearch);
+  }
+
+  Napi::Value setEfSearch(const Napi::CallbackInfo &info)
+  {
+    Napi::Env env = info.Env();
+
+    if (info.Length() != 1)
+    {
+      Napi::Error::New(env, "Expected 1 argument, but got " + std::to_string(info.Length()) + ".")
+          .ThrowAsJavaScriptException();
+      return env.Undefined();
+    }
+    if (!info[0].IsNumber())
+    {
+      Napi::TypeError::New(env, "Invalid the first argument type, must be a Number.").ThrowAsJavaScriptException();
+      return env.Undefined();
+    }
+
+    auto index = dynamic_cast<faiss::IndexHNSW *>(index_.get());
+    index->hnsw.efSearch = info[0].As<Napi::Number>().Int32Value();
+    return env.Undefined();
+  }
+
+  static Napi::Object Init(Napi::Env env, Napi::Object exports)
+  {
+    // clang-format off
+    auto func = DefineClass(env, CLASS_NAME, {
+      InstanceMethod("getEfConstruction", &IndexHNSW::getEfConstruction),
+      InstanceMethod("setEfConstruction", &IndexHNSW::setEfConstruction),
+      InstanceMethod("getEfSearch", &IndexHNSW::getEfSearch),
+      InstanceMethod("setEfSearch", &IndexHNSW::setEfSearch),
+      InstanceMethod("ntotal", &IndexHNSW::ntotal),
+      InstanceMethod("getDimension", &IndexHNSW::getDimension),
+      InstanceMethod("isTrained", &IndexHNSW::isTrained),
+      InstanceMethod("add", &IndexHNSW::add),
+      InstanceMethod("train", &IndexHNSW::train),
+      InstanceMethod("search", &IndexHNSW::search),
+      InstanceMethod("write", &IndexHNSW::write),
+      InstanceMethod("mergeFrom", &IndexHNSW::mergeFrom),
+      InstanceMethod("removeIds", &IndexHNSW::removeIds),
+      InstanceMethod("toBuffer", &IndexHNSW::toBuffer),
+      StaticMethod("read", &IndexHNSW::read),
+      StaticMethod("fromBuffer", &IndexHNSW::fromBuffer),
+    });
+    // clang-format on
+
+    constructor = new Napi::FunctionReference();
+    *constructor = Napi::Persistent(func);
+
+    exports.Set(CLASS_NAME, func);
+    return exports;
+  }
+};
+
 Napi::Object Init(Napi::Env env, Napi::Object exports)
 {
   Index::Init(env, exports);
   IndexFlatL2::Init(env, exports);
   IndexFlatIP::Init(env, exports);
+  IndexHNSW::Init(env, exports);
 
   return exports;
 }
diff --git a/test/IndexHNSW.test.js b/test/IndexHNSW.test.js
new file mode 100644
index 0000000..c9280c3
--- /dev/null
+++ b/test/IndexHNSW.test.js
@@ -0,0 +1,20 @@
+const { IndexHNSW, MetricType } = require('../lib');
+
+describe('IndexHNSW', () => {
+  describe('#constructor', () => {
+    it('1 arg will result in index with default neighbors & metric', () => {
+      const index = new IndexHNSW(2);
+      expect(index.getDimension()).toBe(2);
+    });
+
+    it('2 args will result in index with default metric', () => {
+      const index = new IndexHNSW(2, 20);
+      expect(index.getDimension()).toBe(2);
+    });
+
+    it('3 args will result in index', () => {
+      const index = new IndexHNSW(2, 20, MetricType.METRIC_INNER_PRODUCT);
+      expect(index.getDimension()).toBe(2);
+    });
+  });
+});