Major depression and other psychiatric disorders are common during pregnancy and the postpartum period, yet these disorders remain largely under-diagnosed and under-treated. Developing programs that are uniquely tailored to meet the needs of perinatal psychiatric patients can improve both the quality and acceptability of care. In this report, we describe the development and implementation of a novel mother-baby day hospital service designed to meet the mental health needs of this special population, and present preliminary data regarding treatment acceptability and effectiveness. Our experience using this model of care for the past five years has suggested that specialized units such as this one represent an acceptable, effective, fiscally viable approach to the care of pregnant and postpartum psychiatric patients. Further research is needed to more thoroughly assess the effectiveness of this type of specialized perinatal service.