Distribution of beta thalassemia (HbAβ) was studied among the Bengali Muslim and some Bengali caste groups namely Paundra Kshatriya, Mahisya and Bagdi of South 24 Parganas, West Bengal. The allele frequency of the Paundra Kshatriya, Mahisya, Muslim and Bagdi were 0.050, 0.020, 0.031 and 0.100 respectively. These results were compared with published results from other populations of India. The study reveals that selective pressure of malaria is not operating among these populations.