Introduction: Postpartum period is a transition period but it is being neglected aspect from women health care. Mother's knowledge and education before childbirth is important to be prepared for postpartum. Misinformation about traditions/customs in society are considered irrational, causing confusion in puerperal women, especially for mothers who having their first birth (pirimipara). Method: Analytical observational study, using cross-sectional design. The research conducted in the area of Miri Health Centers, Sragen Regency in December 2012. Result: Mother's age significantly associated with maternal knowledge (p = 0,002). Long marriage was significantly associated with maternal knowledge (p = 0,002). In high knowledge category was 25 pregnant women (83,3%) and moderate knowledge was 5 pregnant women (16,7%).