It has been suggested that vaccination with the measles-mumps-rubella (MMR) vaccine causes autism. The wide-scale use of the MMR vaccine has been reported to coincide with the apparent increase in the incidence of autism. Case reports have described children who developed signs of both developmental regression and gastrointestinal symptoms shortly after MMR vaccination.A review of the literature revealed no convincing scientific evidence to support a causal relationship between the use of MMR vaccines and autism. No primate models exist to support the hypothesis. The biological plausibility remains questionable and there is a sound body of epidemiological evidence to refute the hypothesis. The hypothesis has been subjected to critical evaluation in many different ways, using techniques from molecular biology to population-based epidemiology, and with a vast number of independent researchers involved, none of which has been able to corroborate the hypothesis.