he is colombian... i think one of his grand parents was puerto rican tho
According to his imdb page he says he's Puerto Rcan, Italian, and Lebanese.
I did check google just now too, says his dad is Puerto Rican and his mom's Colombian.
Edit: Then from wiki
John Leguizamo was born in Bogotį, Colombia, to Alberto and Luz Leguizamo. According to Leguizamo, his paternal grandfather was of Puerto Rican and Italian descent and his maternal grandfather was Lebanese. Leguizamo has also described himself as being of Amerindian and Mestizo heritage. Leguizamo's father was once an aspiring film director and studied at Cinecittą, but eventually dropped out due to lack of finances. When Leguizamo was four years old, his family emigrated to the United States and lived in various neighborhoods of Queens in New York City, including Jackson Heights.