A.c. measurements were preformed on bulk samples of Ca1-x Sr (x) TiO3 (CST) perovskites with x = 0, 0.1 and 0.5 as a function of temperature range 300-450 K and frequency range 10(3)-10(5) Hz . The experimental results indicate that the a.c. conductivity sigma(a.c.)(omega), dielectric constant epsilon' and dielectric loss epsilon'' depend on the temperature and frequency. The a.c. conductivity as a function of frequency is well described by a power law A omega(S) with s the frequency exponent. The obtained values of s > 1 decrease with increasing temperature. The present results are compared to the principal theories that describe the universal dielectric response (UDR) behavior.