OBJECTIVE: Postnatal care is an important issue in maintaining and promoting maternal and neonatal health. However, utilization of postpartum maternal health care services is at a low rate in many countries. This study was aimed to investigate the impact of integrated obstetric and neonatal services on utilization rates of postnatal health care service among mothers. METHODS: This study was performed among a total of 4193 mothers who gave birth at Maternity Unit of Golcuk Necati Celik State Hospital of Kocaeli Province between 2010 and 2013. All mothers were called back to postnatal care clinic (PNC) for newborn hearing test (NHT) screenings, neonatal and maternal care within two weeks after delivery. The deliveries after, (n=3093) and before (n=1100) utilization of integrated services were compared as for postnatal service utilization rates. RESULTS: Utilization rates of neonatal health care, NHT and postpartum maternal health care services significantly increased after implementation of integrated services (p<0.0001). Especially maternal service utilization rates increased from 34% to 99 percent. CONCLUSION: Integration of newborn and maternal health care services as a unit increases the utilization of PNC services.