diff --git a/opentelemetry-proto/Cargo.toml b/opentelemetry-proto/Cargo.toml
index ff7e428405..7925e53826 100644
--- a/opentelemetry-proto/Cargo.toml
+++ b/opentelemetry-proto/Cargo.toml
@@ -46,7 +46,7 @@ testing = ["opentelemetry/testing"]
 # add ons
 internal-logs = ["tracing"]
 with-schemars = ["schemars"]
-with-serde = ["serde", "hex"]
+with-serde = ["serde", "hex", "base64"]
 
 [dependencies]
 tonic = { workspace = true, optional = true, features = ["codegen", "prost"] }
@@ -57,6 +57,7 @@ schemars = { version = "0.8", optional = true }
 serde = { workspace = true, optional = true, features = ["serde_derive"] }
 hex = { version = "0.4.3", optional = true }
 tracing = {workspace = true, optional = true} # optional for opentelemetry internal logging
+base64 = { version = "0.22.1", optional = true }
 
 [dev-dependencies]
 opentelemetry = { features = ["testing"], path = "../opentelemetry" }
diff --git a/opentelemetry-proto/src/proto.rs b/opentelemetry-proto/src/proto.rs
index 792e1fc945..13a28ce2a4 100644
--- a/opentelemetry-proto/src/proto.rs
+++ b/opentelemetry-proto/src/proto.rs
@@ -56,6 +56,11 @@ pub(crate) mod serializers {
                 map.serialize_entry("intValue", &i.to_string());
                 map.end()
             }
+            Some(Value::BytesValue(b)) => {
+                let mut map = serializer.serialize_map(Some(1))?;
+                map.serialize_entry("bytesValue", &base64::encode(b));
+                map.end()
+            }
             Some(value) => value.serialize(serializer),
             None => serializer.serialize_none(),
         }
@@ -127,8 +132,10 @@ pub(crate) mod serializers {
                             value = Some(any_value::Value::KvlistValue(kv));
                         }
                         "bytesValue" => {
-                            let bytes = map.next_value()?;
-                            value = Some(any_value::Value::BytesValue(bytes));
+                            let base64: String = map.next_value()?;
+                            let decoded = base64::decode(base64.as_bytes())
+                                .map_err(|e| de::Error::custom(e))?;
+                            value = Some(any_value::Value::BytesValue(decoded));
                         }
                         _ => {
                             //skip unknown keys, and handle error later.
diff --git a/opentelemetry-proto/tests/json_serde.rs b/opentelemetry-proto/tests/json_serde.rs
index 389541cce7..a6552d6570 100644
--- a/opentelemetry-proto/tests/json_serde.rs
+++ b/opentelemetry-proto/tests/json_serde.rs
@@ -274,12 +274,20 @@ mod json_serde {
                                 kind: 2,
                                 start_time_unix_nano: 1544712660000000000,
                                 end_time_unix_nano: 1544712661000000000,
-                                attributes: vec![KeyValue {
+                                attributes: vec![
+                                  KeyValue {
                                     key: String::from("my.span.attr"),
                                     value: Some(AnyValue {
                                         value: Some(Value::StringValue(String::from("some value"))),
                                     }),
-                                }],
+                                  },
+                                  KeyValue {
+                                    key: String::from("my.span.bytes.attr"),
+                                    value: Some(AnyValue {
+                                        value: Some(Value::BytesValue(vec![0x80, 0x80, 0x80])),
+                                    }),
+                                  },
+                                ],
                                 dropped_attributes_count: 1,
                                 events: vec![Event {
                                     time_unix_nano: 1544712660500000000,
@@ -369,6 +377,12 @@ mod json_serde {
                   "value": {
                     "stringValue": "some value"
                   }
+                },
+                {
+                  "key": "my.span.bytes.attr",
+                  "value": {
+                    "bytesValue": "gICA"
+                  }
                 }
               ],
               "droppedAttributesCount": 1,