The artistic director who has helped shape the Alvin Ailey American Dance Theater for nearly two decades says she plans to retire.

Judith Jamison (JAM-ih-son) said Thursday she will step down in 2011. She joined the New York-based modern dance company in 1965 and became artistic director in 1989, shortly after founder Alvin Ailey’s death.

Jamison is 64. During her tenure, the ensemble has created a bachelor’s degree program with Fordham University, expanded its performance schedule and built a $56 million headquarters on Manhattan’s West Side.

The troupe has performed worldwide.