Abstract: In this study, investigations on the biology and distribution of Cadelle (Tenebroides mauritanicus Linneaus (Coleoptera: Trogossitidae)) were carried out in Bursa Province, from 1996 to 1998. The studies were conducted in the laboratory at constant temperature of 27±1°C, 65±5% r.h., dark conditions and under natural conditions where T. mauritanicus lives in. At the end of the studies, T. mauritanicus was found two flour factories in Kestel and Osmangazi districts in Bursa Province during 1996-1998. This is the first record about the presence of T. mauritanicus in Bursa, Turkey. In addition, it was determined that the first adults emerged at the beginning of June. In the laboratory studies, the eggs laid by female developed on grain hatched in 4.01±0.48 days. The number of eggs which laid by adult beetles developed on grain was 103±78.8 and the ratio of hatching was 95%. Emerging larvae usually pass through 5 instars. Average development duration of larvae feeding on grain was 171±106.8 days. Pupal stage lasted average 12 days. Preoviposition was found average 15.2 days. Thus, development period was found minimum 67, maximum 342 days and one generation completed in average 205.8 days. In addition, sexual ratio (female:male) of adults feeding on grain was 2:1.