Bacillus thuringiensis is distributed ubiquitously in the agricultural soil of Bangladesh. Simple correlation and regression analyses showed that the soil sand percentage and the available copper levels had significant negative and positive contributions, respectively, to the abundance and distribution of B. thuringiensis in the agricultural soil. Among the isolates, only 2.5% of strains showed larvicidal activity against the mosquito Culex quinquefasciatus. The larvicidal potency LD50 varied from 3.5 x 10(3) to 9.5 x 10(7) spores per milliliter among the isolates. Copyright 1997 Academic Press. Copyright 1997 Academic Press