Aims and method Communication of responsibility for lithium monitoring and the flow of information between primary and secondary care was assessed by postal questionnaire. Guidelines were then introduced and a re-audit carried out two years later. Results Initial audit showed that the doctor responsible for lithium monitoring was only identifiable in 59% of cases. The majority of general practitioners had received information about monitoring from the consultant prior to taking on the task. Following the introduction of guidelines re-audit showed a marked increase in identification of the responsible professional to 87.5% of cases. There was also a shift towards monitoring in primary care. Clinical implications Communication between primary and secondary care is vital and can be improved by guidelines.