Preheat oven to 375 degrees F (190 degrees C). Lightly grease a 7x11 inch baking dish.
In a medium bowl, mix together the cream cheese and mayonnaise until smooth. Mix in the artichoke hearts, spinach and Parmesan cheese. Season with garlic and lemon juice. Spread evenly into the prepared baking dish.
Bake covered for 20 minutes. Remove the cover, and let the dish bake uncovered for 5 more minutes, or until the surface is lightly browned.