diff --git a/coverage_config.json b/coverage_config.json
index ecf738b..750586a 100644
--- a/coverage_config.json
+++ b/coverage_config.json
@@ -1 +1 @@
-{"coverage_score": 92.4, "exclude_path": "", "crate_features": ""}
+{"coverage_score": 92.5, "exclude_path": "", "crate_features": ""}
diff --git a/src/response.rs b/src/response.rs
index 216a43c..5e0cb79 100644
--- a/src/response.rs
+++ b/src/response.rs
@@ -27,6 +27,8 @@ pub enum StatusCode {
     InternalServerError,
     /// 501, Not Implemented
     NotImplemented,
+    /// 503, Service Unavailable
+    ServiceUnavailable,
 }
 
 impl StatusCode {
@@ -40,6 +42,7 @@ impl StatusCode {
             StatusCode::NotFound => b"404",
             StatusCode::InternalServerError => b"500",
             StatusCode::NotImplemented => b"501",
+            StatusCode::ServiceUnavailable => b"503",
         }
     }
 }
@@ -285,5 +288,6 @@ mod tests {
         assert_eq!(StatusCode::NotFound.raw(), b"404");
         assert_eq!(StatusCode::InternalServerError.raw(), b"500");
         assert_eq!(StatusCode::NotImplemented.raw(), b"501");
+        assert_eq!(StatusCode::ServiceUnavailable.raw(), b"503");
     }
 }