We report nurses' attitudes towards the single checking of medications before and after the implementation of this procedure in an acute health-care setting. Data from a pre-implementation survey confirmed that some nurses held strong views against single checking. Following this survey, the hospital's medication administration policy was revised, a single checking resource manual was developed, 1–2 h nurse education sessions were held, the competencies of nurses to single check and to administer medications were assessed, and single checking was successfully piloted before hospital-wide implementation. Data from a survey conducted 18 months after the implementation indicated that nurses welcomed the single checking medication procedure, felt more confident using single checking and perceived that it made them more accountable for administering medications. The findings provide evidence that nurses' attitudes to single checking change remarkably in favour of its use with education and experience using this procedure.