OBJECTIVE: To compare the pregnancy outcome between high-order multiple and twin pregnancies. DESIGN: Matched-pair retrospective analysis. SETTING: University teaching hospital, Hong Kong. PATIENTS: Patient records from 38 high-order multiple pregnancies that were delivered over a period of 15 years, and those from matched twin pregnancies. MAIN OUTCOME MEASURES: Obstetric and perinatal outcomes. RESULTS: The incidence of high-order multiple pregnancies increased over the study period in association with the more frequent practice of ovulation induction and other assisted reproductive techniques. High-order multiple pregnancies were associated with a higher incidence of maternal complications and a significantly higher perinatal mortality rate than were twin pregnancies. CONCLUSION: Efforts should be made to prevent multiple pregnancies by carefully monitoring ovulation treatment and by limiting the number of embryos transferred.