We have evaluated the effect of transforming growth factor beta‐1 (TGF beta‐1) on proliferation and fusion of cultured ovine satellite cells isolated from 5‐month‐old wether lambs. The isolation and culture protocols were validated by clonal analysis of the original cell preparation and assessment of proliferation and fusion of control cultures. Approximately 85% of the original cells isolated were myogenic as assessed by clonal analysis. The ovine cells doubled approximately every 18 hours during their exponential growth period and achieved a maximum percent fusion of 39.5% after 144 hours in culture. TGF beta‐1 inhibited fusion of these cells in a dose‐dependent manner with half‐maximal inhibition occurring at.08 ng/ml. Maximal inhibition (95% suppression) occurred between.1 and.5 ng/ml. TGF Beta‐1 (.05–3.0 ng/ml) did not inhibit proliferation of cultured ovine satellite cells in serum‐containing medium or in serum‐free defined medium. In contrast, TGF beta‐1 did significantly suppress serum‐stimulated proliferation of either porcine or bovine satellite cells that were isolated by using a procedure identical to that used to isolate the ovine satellite cells. Thus, proliferation of ovine satellite cells appears to respond differently to TGF beta‐1 than does proliferation of either porcine or bovine satellite cells.