diff --git a/HISTORY.md b/HISTORY.md
index d5a1b5b33..76d6abac6 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,7 @@ unreleased
 
   * Add `application/vnd.balsamiq.bmpr`
   * Add `application/vnd.microsoft.portable-executable`
+  * Add `application/x-ns-proxy-autoconfig`
 
 1.9.1 / 2015-04-19
 ==================
diff --git a/db.json b/db.json
index 13c10cd4c..d5aa78782 100644
--- a/db.json
+++ b/db.json
@@ -4381,6 +4381,10 @@
     "source": "apache",
     "extensions": ["nc","cdf"]
   },
+  "application/x-ns-proxy-autoconfig": {
+    "compressible": true,
+    "extensions": ["pac"]
+  },
   "application/x-nzb": {
     "source": "apache",
     "extensions": ["nzb"]
diff --git a/src/custom.json b/src/custom.json
index a37e00997..1aefd8db4 100644
--- a/src/custom.json
+++ b/src/custom.json
@@ -227,6 +227,14 @@
   "application/x-mpegurl": {
     "compressible": false
   },
+  "application/x-ns-proxy-autoconfig": {
+    "compressible": true,
+    "extensions": ["pac"],
+    "sources": [
+      "https://web.archive.org/web/20070602031929/http://wp.netscape.com/eng/mozilla/2.0/relnotes/demo/proxy-live.html",
+      "https://en.wikipedia.org/wiki/Proxy_auto-config#The_PAC_File"
+    ]
+  },
   "application/x-pkcs12": {
     "compressible": false
   },