A series of a complex perovskite CaxSr((1-x))TiO(3) (CST) where (0 less than or equal to x less than or equal to 1) has been prepared by mechanical mixing of their oxides (CaTiO3 and SrTiO3). X-ray diffraction showed that no traces of other compounds and the line widths indicated that the products were homogeneous. The d.c. conductivity of the sample were measured over the range of temperature between 303-800 K. Temperature dependent of d.c. measurement revealed that the conductivity is thermally activated. Over the low temperature range between (333-573 K) for CaTiO3, (353-483 K) for Ca0.7Sr0.3TiO3 and (373-423 K) for Ca0.5Sr0.5TiO3 a semiconductor-metal behavior was observed. From the relationship between activation energy E-a and the compositions, it has been found that E-a goes through a minimum around 50% Sr-fraction. The field lowering coefficient beta is evaluated experimentally. (C) 2004 Kluwer Academic Publishers.