BMP-11/GDF-11 and Myostatin/GDF-8 are both members of the TGF-beta superfamily that can activate SMAD2/3 phosphorylation via the type I receptors ALK4, ALK5, or ALK7. We tested the ability of BMP-11 and Myostatin to promote self-renewal of human embryonic stem cells (hESC) under feeder-free and serum-free culture conditions in short term (1 week) and medium term cultures (10 weeks). We show that hESC cultured in serum-free medium supplemented with either 20 ng/mL Myostatin or 20 ng/mL BMP-11 maintain the colony and cellular morphology of undifferentiated hESC, maintain POU5f1, NANOG, TRA-1-60, and SSEA4 expression, and display increased SMAD2/3 phosphorylation, similar to hESC cultured in mouse embryonic fibroblast feeder-CM or 20 ng/mL Activin-A. The type I TGF-beta receptor inhibitor SB431542 totally inhibited the maintenance activity of both Myostatin or BMP-11 supplemented medium. Our data show that members of the TGF-beta superfamily, other than Activin-A and GDF3, are able to maintain hES cells in an undifferentiated state under feeder free conditions.