diff --git a/Cargo.lock b/Cargo.lock
index 2bb97a6a..d35a745a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -29,6 +29,16 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "ctor"
+version = "0.1.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d2301688392eb071b0bf1a37be05c469d3cc4dbbd95df672fe28ab021e6a096"
+dependencies = [
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.10.1"
@@ -117,6 +127,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
 dependencies = [
  "cfg-if",
+ "value-bag",
 ]
 
 [[package]]
@@ -125,6 +136,24 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
+[[package]]
+name = "proc-macro2"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "134c189feb4956b20f6f547d2cf727d4c0fe06722b20a0eec87ed445a97f92da"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "regex"
 version = "1.7.0"
@@ -156,6 +185,17 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "termcolor"
 version = "1.1.3"
@@ -165,6 +205,28 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "unicode-ident"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
+
+[[package]]
+name = "value-bag"
+version = "1.0.0-alpha.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2209b78d1249f7e6f3293657c9779fe31ced465df091bbd433a1cf88e916ec55"
+dependencies = [
+ "ctor",
+ "version_check",
+]
+
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index 7a1ae457..3d565de5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,6 +42,7 @@ color = ["dep:termcolor"]
 auto-color = ["dep:is-terminal", "color"]
 humantime = ["dep:humantime"]
 regex = ["dep:regex"]
+kv_unstable = ["log/kv_unstable"]
 
 [dependencies]
 log = { version = "0.4.8", features = ["std"] }
diff --git a/src/fmt/mod.rs b/src/fmt/mod.rs
index ded40278..3808c7ce 100644
--- a/src/fmt/mod.rs
+++ b/src/fmt/mod.rs
@@ -51,6 +51,9 @@ pub(crate) mod glob {
     pub use super::{Target, TimestampPrecision, WriteStyle};
 }
 
+#[cfg(feature = "kv_unstable")]
+use log::kv;
+
 /// Formatting precision of timestamps.
 ///
 /// Seconds give precision of full seconds, milliseconds give thousands of a
@@ -149,6 +152,9 @@ pub(crate) struct Builder {
     pub custom_format: Option<FormatFn>,
     pub format_suffix: &'static str,
     built: bool,
+
+    #[cfg(feature = "kv_unstable")]
+    pub format_key_values: bool,
 }
 
 impl Builder {
@@ -181,6 +187,9 @@ impl Builder {
                     indent: built.format_indent,
                     suffix: built.format_suffix,
                     buf,
+
+                    #[cfg(feature = "kv_unstable")]
+                    key_values: built.format_key_values,
                 };
 
                 fmt.write(record)
@@ -200,6 +209,9 @@ impl Default for Builder {
             custom_format: None,
             format_suffix: "\n",
             built: false,
+
+            #[cfg(feature = "kv_unstable")]
+            format_key_values: true,
         }
     }
 }
@@ -221,6 +233,9 @@ struct DefaultFormat<'a> {
     indent: Option<usize>,
     buf: &'a mut Formatter,
     suffix: &'a str,
+
+    #[cfg(feature = "kv_unstable")]
+    key_values: bool,
 }
 
 impl<'a> DefaultFormat<'a> {
@@ -231,6 +246,9 @@ impl<'a> DefaultFormat<'a> {
         self.write_target(record)?;
         self.finish_header()?;
 
+        #[cfg(feature = "kv_unstable")]
+        self.write_key_values(record)?;
+
         self.write_args(record)
     }
 
@@ -338,6 +356,45 @@ impl<'a> DefaultFormat<'a> {
         }
     }
 
+    #[cfg(feature = "kv_unstable")]
+    fn write_key_values(&mut self, record: &Record) -> io::Result<()> {
+        if !self.key_values {
+            return Ok(());
+        }
+
+        struct KVVisitor<'a, 'b> {
+            fmt: &'a mut DefaultFormat<'b>,
+            visited: bool,
+        }
+
+        impl<'kvs> kv::Visitor<'kvs> for KVVisitor {
+            fn visit_pair(
+                &mut self,
+                key: kv::Key<'kvs>,
+                value: kv::Value<'kvs>,
+            ) -> Result<(), kv::Error> {
+                if self.visited {
+                    write!(self.fmt.buf, ", ")?;
+                } else {
+                    self.visited = true;
+                }
+                write!(self.fmt.buf, "{}={}", key, value)?;
+                Ok(())
+            }
+        }
+
+        let mut visitor = KVVisitor {
+            fmt: self,
+            visited: false,
+        };
+        record.key_values().visit(&mut visitor)?;
+        if visitor.visited {
+            write!(self.buf, ": ")?;
+        }
+        Ok(())
+    }
+
+
     fn write_args(&mut self, record: &Record) -> io::Result<()> {
         match self.indent {
             // Fast path for no indentation
diff --git a/src/logger.rs b/src/logger.rs
index 6c8a00d4..99cb7942 100644
--- a/src/logger.rs
+++ b/src/logger.rs
@@ -312,6 +312,13 @@ impl Builder {
         self
     }
 
+    /// Configures if keys and values should be included.
+    #[cfg(feature = "kv_unstable")]
+    pub fn format_key_values(&mut self, value: bool) -> &mut Self {
+        self.format.format_key_values = value;
+        self
+    }
+
     /// Adds a directive to the filter for a specific module.
     ///
     /// # Examples