diff --git a/axum/CHANGELOG.md b/axum/CHANGELOG.md
index f9d0db4c..03a23dbb 100644
--- a/axum/CHANGELOG.md
+++ b/axum/CHANGELOG.md
@@ -7,11 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
+- **fixed:** `sse::Event` will no longer drop the leading space of data, event ID and name values
+  that have it ([#600])
 - **fixed:** `sse::Event` is more strict about what field values it supports, disallowing any SSE
   events that break the specification (such as field values containing carriage returns) ([#599])
 - **added:** `axum::AddExtension::layer` ([#607])
 
 [#599]: https://github.com/tokio-rs/axum/pull/599
+[#600]: https://github.com/tokio-rs/axum/pull/600
 [#607]: https://github.com/tokio-rs/axum/pull/607
 
 # 0.4.2 (06. December, 2021)
diff --git a/axum/src/response/sse.rs b/axum/src/response/sse.rs
index b8dbe23b..8fa77f13 100644
--- a/axum/src/response/sse.rs
+++ b/axum/src/response/sse.rs
@@ -315,7 +315,7 @@ impl fmt::Display for Event {
         }
 
         if let Some(event) = &self.event {
-            "event:".fmt(f)?;
+            "event: ".fmt(f)?;
             event.fmt(f)?;
             f.write_char('\n')?;
         }
@@ -323,7 +323,7 @@ impl fmt::Display for Event {
         match &self.data {
             Some(DataType::Text(data)) => {
                 for line in data.split('\n') {
-                    "data:".fmt(f)?;
+                    "data: ".fmt(f)?;
                     line.fmt(f)?;
                     f.write_char('\n')?;
                 }
@@ -338,7 +338,7 @@ impl fmt::Display for Event {
         }
 
         if let Some(id) = &self.id {
-            "id:".fmt(f)?;
+            "id: ".fmt(f)?;
             id.fmt(f)?;
             f.write_char('\n')?;
         }
@@ -452,3 +452,12 @@ impl KeepAliveStream {
         Poll::Ready(event)
     }
 }
+
+#[test]
+fn leading_space_is_not_stripped() {
+    let no_leading_space = Event::default().data("\tfoobar");
+    assert_eq!(no_leading_space.to_string(), "data: \tfoobar\n\n");
+
+    let leading_space = Event::default().data(" foobar");
+    assert_eq!(leading_space.to_string(), "data:  foobar\n\n");
+}