American Tribal Style (ATS) is an improvisational style of belly dance created by Carolena Nericcio of San Francisco's world renowned troupe FatChanceBellyDance. It is a modern, American style inspired by the dance, music, and costumes of tribal and gypsy cultures from the Middle East, India, North Africa and Spain. It is the foundation for many other spin-off styles of tribal and fusion belly dance.

The slow dances are mesmerizing, strong and beautiful to watch, while the fast dances are cheerful, very charming in the way that people dance together.

The style consists of a learned vocabulary of moves which can be used to create improvisational dances. The lead dancer combines these moves as she chooses, much like combining words to form sentences. The other dancers follow her seamlessly through subtle non vocal cues. The result is what looks like a well choreographed, synchronized dance. The beauty is that it is spontaneous, adaptable, and interactive. As long as everyone knows the system, you can get up and dance with people you've never met before and look like you've been dancing together for years!