diff --git a/api/src/main/java/org/eclipse/microprofile/health/HealthCheckProcedure.java b/api/src/main/java/org/eclipse/microprofile/health/HealthCheckProcedure.java
index e8010a5..da36b6b 100644
--- a/api/src/main/java/org/eclipse/microprofile/health/HealthCheckProcedure.java
+++ b/api/src/main/java/org/eclipse/microprofile/health/HealthCheckProcedure.java
@@ -27,6 +27,7 @@
  * @author Heiko Braun
  * @since 13.06.17
  */
+@FunctionalInterface
 public interface HealthCheckProcedure {
     HealthStatus perform();
 }