INTRODUCTION: Unplanned out-of-hospital deliveries (UOHDs) have earlier been related to higher perinatal mortality and morbidity, but recent research has not paid much attention to them. Our aim was to evaluate the incidence, characteristics, risk factors, and maternal and perinatal mortality and morbidity in UOHDs in Finland. MATERIAL AND METHODS: We conducted a national register study on births, causes of death and congenital anomalies for all live and stillbirths during 1996-2013. The study group included 1420 infants delivered by mothers with UOHDs. The 1 051 139 infants born in hospitals during the study period were the reference group. Data on maternal and delivery characteristics, obstetric procedures, infants' characteristics, neonatal care unit admissions, diagnoses, congenital anomalies and causes of death were collected. RESULTS: The annual rate of UOHDs increased in 1996-2013 from 46 to 260 per 100 000 deliveries, whereas the number of delivery units decreased from 44 to 29. UOHD infants had five times higher perinatal mortality rates than those delivered in hospitals. The perinatal mortality rate did not change by time in the UOHDs, whereas it diminished among in-hospital deliveries. Maternal morbidity in UOHDs was low. The predictors for UOHDs were delivery after the year 2001, delivery in sparsely populated areas, alcohol, drug abuse and/or smoking during pregnancy, being single, fewer prenatal visits, having delivered earlier and birthweight <2500 g. UOHD was one of the predictors of perinatal morbidity and mortality. Among the UOHD cases, the predictors of perinatal morbidity or mortality included low birthweight and preterm delivery. Time period seemed not to predict morbidity or mortality. CONCLUSIONS: The UOHD rate increased, probably due to multifactorial causes, including living in area with low population density and short duration of labor. UOHD was a significant predictor of perinatal morbidity or mortality, but the numbers were very small. Neonatal morbidity and mortality in UOHDs did not seem to be related to the area or time period of birth.