The purpose of this study was to examine selected mechanical factors involved in the tennis serve. Special emphasis was placed on identifying factors which distinguish players of different serving abilities. Ten right-handed female tennis players, five ranked, and five unranked, were evaluated, following filming with a high-speed camera, on the basis of five good and five fault serves. The ranked players were seen to differ from the unranked players with respect to (a) serving consistency, (b) initial Y-center of gravity values, (c) certain segment angles at the peak of the ball toss and at ball contact, and (d) certain joint angles at the moment of the ball contact.