diff --git a/CHANGELOG.md b/CHANGELOG.md
index 733e209..80654b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [0.24.1]
 
+### Added
+
+- `EncodeGaugeValue` is implemented for `usize` and `isize`, and
+  `EncodeCounterValue` is implemented for `usize`. See [PR 282].
+
 ### Fixed
 
 - `EncodeGaugeValue`, `EncodeCounterValue` and `EncodeExemplarValue` now use
@@ -25,6 +30,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [PR 242]: https://github.com/prometheus/client_rust/pull/242
 [PR 245]: https://github.com/prometheus/client_rust/pull/245
 [PR 246]: https://github.com/prometheus/client_rust/pull/246
+[PR 281]: https://github.com/prometheus/client_rust/pull/281
+[PR 282]: https://github.com/prometheus/client_rust/pull/282
 
 ## [0.24.0]
 
diff --git a/src/encoding.rs b/src/encoding.rs
index 46cc1b5..44ec0ef 100644
--- a/src/encoding.rs
+++ b/src/encoding.rs
@@ -618,6 +618,21 @@ impl EncodeGaugeValue for u64 {
     }
 }
 
+impl EncodeGaugeValue for isize {
+    fn encode(&self, encoder: &mut GaugeValueEncoder) -> Result<(), std::fmt::Error> {
+        // Is infallible for 32-bit or 64-bit platforms
+        encoder.encode_i64(i64::try_from(*self).map_err(|_err| std::fmt::Error)?)
+    }
+}
+
+impl EncodeGaugeValue for usize {
+    fn encode(&self, encoder: &mut GaugeValueEncoder) -> Result<(), std::fmt::Error> {
+        // For 32-bit platforms this is infallible, for 64-bit platforms the argument is the same
+        // as the one for u64 values
+        encoder.encode_i64(i64::try_from(*self).map_err(|_err| std::fmt::Error)?)
+    }
+}
+
 impl EncodeGaugeValue for f64 {
     fn encode(&self, encoder: &mut GaugeValueEncoder) -> Result<(), std::fmt::Error> {
         encoder.encode_f64(*self)
@@ -686,6 +701,13 @@ impl EncodeCounterValue for u64 {
     }
 }
 
+impl EncodeCounterValue for usize {
+    fn encode(&self, encoder: &mut CounterValueEncoder) -> Result<(), std::fmt::Error> {
+        // Is infallible for 32-bit and 64-bit platforms
+        encoder.encode_u64(u64::try_from(*self).map_err(|_err| std::fmt::Error)?)
+    }
+}
+
 impl EncodeCounterValue for f64 {
     fn encode(&self, encoder: &mut CounterValueEncoder) -> Result<(), std::fmt::Error> {
         encoder.encode_f64(*self)