Ionic densities of sputtered titanium (Ti) in rf magnetron sputtering were measured using an optical absorption method. Measurements of ionic densities of sputtered Ti were made by varying pressure of Ar gas, applied rf power and distance from the target., The densities of Ti atoms were measured using an atomic absorption method for deriving ionization fraction of sputtered Ti. At the rf power of 200 W, ionic densities of Ti were found to be lower than 1.0 X 10(10) cm(-3) indicating that ionization fractions were of the order of several percentages at Ar pressures lower than the pressure of several Pascals that is used in conventional sputtering. The ionic density increased with increasing pressure and reached a maximum value of 4.8 X 10(10) cm(-3) at the Ar pressure of 21 Pa for z = 15 min where z is axial distance with origin at the Ti target surface. Also, both ionic and atomic densities of sputtered Ti increased monotonically with increasing rf power resulting in an almost constant value of ionization fraction at the Ar pressure of 7 Pa. Probe measurements indicated that fractions of Ti ion were around 30%-40% of the total ionic density which at pressures higher than several Pa was mainly made up of Ar ion. The ionization rate of electron impact for Ti and Ar is discussed based on measurements made by the authors. (C) 2003 American Vacuum Society.