Aim: To identify the underlying factors that may affect the changing rates of modes of delivery over the decades based on Robson-10 group classification system (TGCS) in a single tertiary health care center. Materials and methods: This study included data from 10,458 deliveries in 1976, 1986, 1996, 2006, and 2016 with fetuses more than or equal to 500 g at the Department of Obstetrics and Gynecology at Hacettepe University Hospital. Patient characteristics and the mode of delivery were evaluated according to the TGCS. Results: The cesarean section (CS) rates were 11.4% (304/2668), 19.2% (459/2393), 44.7% (783/1751), 69.3% (1213/1751), and 77.9% (1477/1895) in 1976, 1986, 1996, 2006, and 2016, respectively. CS has become the preferred method of delivery for multiple pregnancies and breech presentations over the years. TGCS Group 5 was the greatest contributor to increased CS ratios. Relative contributions of TGCS Groups 1 and 3 were decreased and relative contributions of Groups 2 and 4 were increased. Operative vaginal deliveries decreased over the years. Conclusion: In conclusion, effective management of labor induction, choosing vaginal delivery for appropriate breech presentations and multifetal pregnancies, proper education of obstetricians for operative vaginal delivery and objective evaluation of labor dystocia might be key points in CS rate debates.