Abstract: Chromosomal information of species are essential since species are considered to be the objective reality of some particular genetic continuity and karyological studies has come to recognized as an important tool in understanding the problem of taxonomy and biology. In the present investigation T. castaneum has been studied with the view to determine the diploid (2n) number, morphology, centromeric index, sex determination mechanism, C-banding pattern and NOR localization which are essential to obtain a complete knowledge of cytogenetics of any animal. The observations revealed that karyotype of T. castaneum, showed a diploid number of 2n = 20 chromosome and sex determining mechanism was of “parachute type” due to the X and y chromosome (9AA + Xyp). C- banded preparations showed positive staining in centromeric regions of all autosomes. In sex chromosomes only Xp chromosome indicated heterochromatised block. Nucleolar organizing regions were also localized.