Nowadays, there is a general opinion in both scientific and engineering community that there is an urgent need for the development of cheap, reliable sensors for the control and measuring systems, for the automation of services and for the industrial and scientific apparatus. Although much research has been focused on sensors based on SnO2 and binary oxides technology, other inorganic oxides are receiving increased attention. These include binary oxides, such as oxides of titanium, tungsten, gallium and more ternary oxides. Compounds having pervoskite structures are among one of the most important classes of ternary oxides. Barium titanate (BaTiO3) is one of the most intensively investigated ferroelectrics, and has been widely used in electronic industry in applications for capacitors, thermocouples, transducers, sensors and actuators.But BaTiO3 is least familiar for gas sensor applications.So, the objective of the present investigation is to develop screen printed thick film gas sensors based on pure and modified BaTiO3, BaxSr1-xTiO3 (x = 0.67, 0.80, 0.87), and (Ba0.8Sr0.2) (Sn0.8Ti0.2)O3 different interfering gases.