Data from a panel of New York Dairy farms were used to estimate rbST adoption functions, and to measure the impact of rbST on milk output and profitability per cow. Adoption results are consistent with previous rbST adoption studies. Farm size, productivity and education of the principal operator are the most important explanatory variables influencing adoption. The use of rbST was found to significantly increase milk output per cow net of other explanatory variables, correcting for self-selection with respect to rbST use. The impact on profits, was, however, not statistically different from zero at any conventional statistical significance level.