The bacterium, Bacillus thuringiensis is one of the most important insect microbial control agents.Practical description of its isolation and purification procedures and investigating its distribution in soilsamples are some primary necessities of using, quick and precise, molecular methods. In this study,preliminary screening of the bacterium was performed using 112 of forest, urban, non-vegetative, agriculturalcrops and orchards soil samples. Final validation was made by 43 samples. Three different media (LB-A, T3and CCY) and two staining procedure were compared, too. Following last screening of 6, 6, 9, 10 and 11samples of the soil types, 12, 33, 97, 50 and 71 colony were isolated, respectively. Evaluated ratios ofcolonies to samples were 2, 5.5, 10.8, 5 and 6.4, respectively. Remarkable frequency of bacterium in nonvegetativearea showed weak relationship of its existence and distribution to insect host occurrence.