ABSTRACT This paper studies the effective parameters of a skilled service in playing tennis and determines their relationship with skill deals. Effective service in tennis plays an important role in gaining more desirable result and the most important factor of success in getting scores depends on the player's skills in serving an effective service. The characteristics of a good service are the high speed of the ball and the precision of landing the ball. The several parameters affecting on these two characteristic in the service, are studied in this paper. Therefore, the Kinematic parameters of 8 Iranian professional tennis athletes of first division tennis league and also 8 non-professional Iranian athletes who exercise about 3 sessions a week were extracted. After land marking these athletes, by use of two high-frequency cameras, pictures were recorded when the tennis players were serving the services. The investigation on the results of these tests is performed by three dimensional motion analyses. The pictures are analyzed with the WinAnalyze software. Therefore, in this paper, the most important effective parameters in serving a successful service are detected