Contested reports associating the MMR vaccine with autism have resulted in diminished confidence and uptake of the vaccine in the UK. This postal survey of parent's decisions, attitudes and use of information about MMR immunisation was constructed from questions derived from in-depth qualitative work. The setting was a Primary Care Trust in northeast England (N=996). Both MMR-accepting and refusing parents were supportive of immunisation, yet the high level of concern about the safety of the vaccine expressed even by parents who had immunised their children is worrying in its implications for public confidence and trust in health care. The findings suggest that the ability of practitioners to provide effective professional advice about MMR vaccine could be undermined if a government were to directly promote the vaccine to parents. Practitioners should continue to provide parents with accurate information, while communicating respect for parents' intentions to protect their children's health.