diff --git a/src/Convert/UnbasedUnsized.hs b/src/Convert/UnbasedUnsized.hs
index ed208e5..790a3cc 100644
--- a/src/Convert/UnbasedUnsized.hs
+++ b/src/Convert/UnbasedUnsized.hs
@@ -188,6 +188,8 @@ convertExpr _ (Cast te e) =
     Cast te $ convertExpr SelfDetermined e
 convertExpr _ (Concat exprs) =
     Concat $ map (convertExpr SelfDetermined) exprs
+convertExpr context (Pattern [(":default", e @ UU{})]) =
+    convertExpr context e
 convertExpr _ (Pattern items) =
     Pattern $ zip
     (map fst items)
diff --git a/test/basic/unbased_unsized_default.sv b/test/basic/unbased_unsized_default.sv
new file mode 100644
index 0000000..4712d97
--- /dev/null
+++ b/test/basic/unbased_unsized_default.sv
@@ -0,0 +1,11 @@
+module Example(inp);
+    input [4][5] inp;
+    initial #1 $display("%b", inp);
+endmodule
+
+module top;
+    Example e1('{default:'0});
+    Example e2('{default:'1});
+    Example e3('{default:'x});
+    Example e4('{default:'z});
+endmodule
diff --git a/test/basic/unbased_unsized_default.v b/test/basic/unbased_unsized_default.v
new file mode 100644
index 0000000..e81923d
--- /dev/null
+++ b/test/basic/unbased_unsized_default.v
@@ -0,0 +1,11 @@
+module Example(inp);
+    input [19:0] inp;
+    initial #1 $display("%b", inp);
+endmodule
+
+module top;
+    Example e1({20 {1'sb0}});
+    Example e2({20 {1'sb1}});
+    Example e3({20 {1'sbx}});
+    Example e4({20 {1'sbz}});
+endmodule