diff --git a/aconfig/aconfig_declarations.go b/aconfig/aconfig_declarations.go
index d29e312..71a64dd 100644
--- a/aconfig/aconfig_declarations.go
+++ b/aconfig/aconfig_declarations.go
@@ -73,8 +73,9 @@
 	if len(module.properties.Package) == 0 {
 		ctx.PropertyErrorf("package", "missing package property")
 	}
-	// TODO(b/311155208): Add mandatory check for container after all pre-existing
-	// ones are changed.
+	if len(module.properties.Container) == 0 {
+		ctx.PropertyErrorf("container", "missing container property")
+	}
 
 	// Add a dependency on the aconfig_value_sets defined in
 	// RELEASE_ACONFIG_VALUE_SETS, and add any aconfig_values that