Preheat oven to 400 degrees F. Lightly oil a baking sheet or coat with nonstick spray.
2.In a large pot of boiling salted water, cook potatoes until just tender and parboiled, about 10-13 minutes. Stir in corn during the last 5 minutes of cooking time; drain well.
3.In a small bowl, combine butter, garlic and Old Bay Seasoning.
4.Place potatoes, corn, shrimp and sausage in a single layer onto the prepared baking sheet. Stir in butter mixture and gently toss to combine.
5.Place into oven and bake for 12-15 minutes, or until the shrimp are opaque and corn is tender.
6.Serve immediately with lemon wedges, garnished with parsley, if desired.