Sickle cell disease is observed to occur in significantly high frequencies amongst the tribes of India. It has surged to the fore as an important public health problem among tribal groups, which needs serious attention. This paper presents the distribution of this abnormal genetic problem among scheduled tribes of India, in general and among those of Andhra Pradesh and Orissa states, in detail. Though the prevalence of sickle cell trait is high, the sickle cell disease cases are found to be very low, since all these surveys are made among adults. Most of the sickle cell disease cases might have expired during their early states. Hence, it is attempted to estimate the expected frequencies of disease cases from HbS gene frequencies. Estimations were also made by considering higher levels of inbreeding among these populations.