(Ba0.5Sr0.5)TiO3 (Ba1-xSrxTiO3 with x = 0.5) thin films were deposited on indium tin oxide-coated glass substrate using r.f. magnetron sputtering as a function of film thickness (110-440 nm) at 550 degrees C in order to investigate the thickness dependence of structural and electrical properties. The films were studied by means of scanning electron microscopy and X-ray diffractometry. Dielectric constant epsilon’, dissipation factor tan delta, current-voltage I-V characteristics and breakdown field were also studied. It was observed that the dense films were obtained regardless of him thickness and the thinner film showed the rougher surface. As the thickness of the film increased, the dielectric constant increased and the dissipation factor decreased, becoming finally saturated in dielectric constant and dissipation factor with the increase of film thickness. As the film thickness increased, the leakage current decreased and the breakdown field gradually increased from 1.18 MV cm(-1) at 110 nm to 2.2 MV cm(-1) at 330 nm, and then decreases up to 1.97 MV cm(-1) at 440 nm.