OBJECTIVE: To quantify the impact of long-standing vaccination programmes on notified cases in the Netherlands. DESIGN: Estimates based on model projections of historical morbidity data. METHOD: We collected and digitised previously unavailable monthly case notifications of diphtheria, poliomyelitis, mumps and rubella in the Netherlands over the period 1919-2015. Poisson regression models accounting for seasonality, multi-year cycles, secular trends and auto-correlation were fit to pre-vaccination periods. Cases averted were calculated as the difference between observed and expected cases based on model projections. RESULTS: In the first 13 years of mass vaccinations, case notifications declined rapidly with 18,900 (95%-CI: 12,000-28,600) notified cases of diphtheria averted, 5100 (95%-CI: 2200-13,500) cases of poliomyelitis, and 1800 (95%-CI: 1000-3200) cases of mumps. Vaccination of 11-year-old girls against rubella averted 13700 (95%-CI: 1400-38,300) cases, while universal rubella vaccination averted 700 (95%-CI: 80-2300) cases. CONCLUSION: These findings show that vaccination programmes have contributed substantially to the reduction of infectious diseases in the Netherlands.