In this paper we have carried out an analysis of the predictions of the radiatively driven stellar winds theories on 63 stars belonging to clusters or associations. The spectral types in our sample range from O3 to B0 and all classes of luminosity are considered. The study has been carried out starting from the relationship between the stellar-wind velocity (v edge) obtained from the resonance doublet of CIV for stars observed with the IUE, and the escape velocity. The stellar masses have been obtained from the evolutionary tracks of Maeder and Meynet. Results from recent NLTE analyses with blanketing of lines and winds have been used for the effective temperature.