Thermally stimulated luminescence (TSL) and BaS phosphors doped with Cu and Bi has been studied by exciting with γ-rays (Co60) at room temperature (30°C). In all the cases two prominent glow peaks are observed nearly in the same temperature regions (around 200 and 300°C). The decay has been studied by storing the samples in darkness for different lengths of time after excitation. The trapping parameters, viz. trap depth(E)and frequency factor(S), are calculated from all these results which are in good agreement. It is concluded that the distribution of trapped holes in the neighbourhood of impurities and lattice imperfections is responsible for TSL emission.