Postnatal care is a care provided to women and their babies within 42 days after delivery. A large proportion of maternal and neonatal deaths occur during the first 48 hours after delivery, and these first two days following delivery are critical for monitoring complications arising from the delivery. A cross-sectional study was carried out among targeted population. Total coverage of women in lactating period attending F.H.U in Elbaliana city, Elhegz, Banyhemeel, Abosteet and Al eslah valleges of El baliana district in the period starting 1st of April till end of September 2018. The results showed that the mean percentage level of knowledge of postnatal mothers on selected aspects of postnatal care was 59.9% and the mean level was 11.98 with standard deviation of 4.38. Fifty-seven point seven of the studied women had a good knowledge regarding postnatal services and 42.3% had poor knowledge. In the final regression model, it is found that women younger than 20 years are nearly five times more liable to have poor knowledge regarding postnatal care than those older than 35 years.