Ti6Al4V films were grown onto an UNS S31600 austenitic stainless steel by rf magnetron sputtering. Sample surfaces were analyzed by X-ray diffraction, aiming to characterize film structure, and by energy dispersive spectroscopy, for chemical composition determination. Deposition experiments varying both chamber pressure and plasma power were carried out. The effect of those variations in pressure and power on type of phases formed and their crystal size was appraised. Ti-BCC films with sharp texture and nanometric sized crystals were obtained. Film preferred crystallographic orientation and chemical composition were almost unaffected by variations on both pressure and power. On the other hand, crystal size was highly dependent on deposition parameters. Scherrer's analysis allowed estimating average crystal sizes which ranged between 10 and 30 nm approximately. Lower plasma powers or higher chamber pressures led to smaller film crystals. The role of physical parameters controlling stability of crystal phases and their crystal size is discussed.