Measles, mumps and rubella (MMR) vaccine failure had been reported globally and here, we report that it occurs in India now. MMR vaccinated people have developed acute mumps accompanied by anti-mumps immunoglobulin M. Genotypic characterisation revealed that the circulating mumps strain was genotype C, which is distinct from the vaccine strain of genotype N (L-Zagreb). This is the first report in India to suggest that genotype C is responsible for the present mumps infection. Thus, the present MMR vaccine must be revamped and optimised for its efficacy to prevent any future mumps epidemics.