A retrospective epidemiological survey was conducted to evaluate the incidence and characteristics of thrombocytopenic purpura (TP) reported in France following measles, mumps or rubella vaccination with monovalent or multivalent vaccines. Sixty cases of TP were reported i.e an incidence/100,000 doses of 0.23 and 0.17 for measles or rubella vaccines respectively given alone, to 0.87 for combined measles-rubella vaccine and 0.95 for MMR vaccine. The mean age was 21 +/- 12 months and the delay of diagnosis was 16 +/- 6 days after vaccination. Thrombopenia was severe (mean platelet count: 8000 +/- 6000/mm3) and always associated with purpura. The immediate outcome was favourable in 89.5 per cent of cases. Vaccine-associated TP appears to be similar to acute childhood idiopathic thrombocytopenic purpura but the clear temporal relationship between MMR vaccination and the occurrence of TP make a causal relationship highly plausible. Acute TP seems a rare complication of measles-rubella and MMR vaccination but clinicians had to be informed of the possibility of their occurrence. Acute TP following vaccination should be reported by physicians to their Regional Drug Surveillance Centre.