This study examined determinants of rural and urban postnatal care differentials among newborns in Tanzania. The study used secondary data from the national cross-sectional Demographic and Health Survey (TDHS-MIS) for 2015/2016. Multivariate Oaxaca blinder decomposition was employed to decompose the gap in postnatal care between urban and rural in Tanzania. Findings disclosed that for both areas, place of delivery, childbirth size, and distance to health facilities were statistically significantly associated with low postnatal care. In addition, it was uncovered that ANC visits, media exposure, health insurance, maternal education, and wealth status were statistically significantly associated with high postnatal care. Moreover, distribution variations of socio-economic factors significantly contributed to the reduction in postnatal care. The variation of effects of socio-economic factors on differences in postnatal care seemed to have a significant positive contribution. The study recommends increasing the number of health facilities and re-emphasizing not only the proper utilization of health facility delivery but also emphasizing its quality to promote pertinent postnatal care services.