Prepotency of 5 seed and 9 pollen parents of peach and nectarine, Prunus persica (L.) Batsch, was estimated from analysis of detailed data on 1,131 seedlings. Selections were compared as parents from percentages of transmission of 22 commercially important characteristics in multiple cross progenies. Three composite measures of combining ability delineated two of the selections as superior parents. One parent gave selections worthy of propagation at the rate of 1 per 33 seedlings, while poorer parents required as many as 752 seedlings to produce one selection.