Twenty-seven general practitioners associated with the Department of Community Health and General Practice, TCD, agreed to record details of the drugs prescribed on 30 consecutive GMS prescriptions. Doctors were asked to indicate whether the items they were prescribing were initiated by themselves or by a hospital doctor and whether they agreed with the latter items in terms of their clinical appropriateness and cost. Information on 1,471 prescribed items was obtained from a total of 754 prescriptions. General practitioners initiated 63% of these items, hospital doctors 35% and in 2% the person responsible was unknown. Hospital initiated items accounted for 44.5% of total ingredient costs compared with 54% in general practice. General practitioners agreed with most of the hospital initiated items in terms of their clinical appropriateness and cost. Given the extent of hospital initiated GMS prescribing in this study there is a clear need to differentiate between those items originating in hospital and those in general practice for accountability purposes.