diff --git a/src/cargo/ops/cargo_output_metadata.rs b/src/cargo/ops/cargo_output_metadata.rs
index 9d52fa09ad7..c0a63aa75a2 100644
--- a/src/cargo/ops/cargo_output_metadata.rs
+++ b/src/cargo/ops/cargo_output_metadata.rs
@@ -43,6 +43,7 @@ pub fn output_metadata(ws: &Workspace<'_>, opt: &OutputMetadataOptions) -> Cargo
     Ok(ExportInfo {
         packages,
         workspace_members: ws.members().map(|pkg| pkg.package_id()).collect(),
+        workspace_default_members: ws.default_members().map(|pkg| pkg.package_id()).collect(),
         resolve,
         target_directory: ws.target_dir().into_path_unlocked(),
         version: VERSION,
@@ -58,6 +59,7 @@ pub fn output_metadata(ws: &Workspace<'_>, opt: &OutputMetadataOptions) -> Cargo
 pub struct ExportInfo {
     packages: Vec<SerializedPackage>,
     workspace_members: Vec<PackageId>,
+    workspace_default_members: Vec<PackageId>,
     resolve: Option<MetadataResolve>,
     target_directory: PathBuf,
     version: u32,
diff --git a/tests/testsuite/metadata.rs b/tests/testsuite/metadata.rs
index 547916e7a77..299f5245dd4 100644
--- a/tests/testsuite/metadata.rs
+++ b/tests/testsuite/metadata.rs
@@ -65,6 +65,7 @@ fn cargo_metadata_simple() {
             }
         ],
         "workspace_members": ["foo 0.5.0 (path+file:[..]foo)"],
+        "workspace_default_members": ["foo 0.5.0 (path+file:[..]foo)"],
         "resolve": {
             "nodes": [
                 {