Background: Gliclazide is commonly used in the treatment of diabetes mellitus; however, very little is known regarding the safety of its use in pregnancy. The aims of this study was to examine the rate of maternal hospitalizations, congenital anomalies, and adverse neonatal outcomes in pregnant women treated with gliclazide compared with pregnant women treated with metformin. Methods: Women who used gliclazide during pregnancy (n = 108) between 2003 and 2012 were identified by linking national medication dispensing data with the New South Wales perinatal data collection. A comparison group of women treated with only metformin during pregnancy (n = 108) were selected using propensity score matching. Data on hospital admissions, mortality, and congenital anomalies were extracted to examine the health of mothers and their children across groups. Results: Rates of maternal hospitalizations during pregnancy were not significantly different between women in the two groups (incident rate ratio: 1.10, 95% CI: 0.90-1.34, P = 0.339). There was no significant difference in average birth weight (3402 g compared with 3572 g, P = 0.072), incidence of neonatal hypoglycemia (<4.6% compared with <4.6%, P = 0.684), or congenital anomalies (7.4% compared with 5.6%, P = 0.582) in neonates exposed to gliclazide compared with metformin. Conclusions: The use of gliclazide during pregnancy was not associated with increased maternal hospitalization or neonatal adverse outcomes in comparison with the use of metformin in pregnancy; however, the limited number of exposed pregnancies is a key limitation.