Prescribing Analysis and Cost (PACT) data are sent to all GPs to assist them in monitoring their prescribing. Although the quarterly Standard Reports contain a great deal of information it is not known how GPs make use of it. This paper reports on two linked studies which explore GPs' views on PACT Standard Reports and PACT catalogue data. In the first study, interviews were carried out with 21 GPs in 16 practices selected according to criteria related to their prescribing budget. The interview schedule included questions on how the Standard Reports were used and the amount and ease of understanding of the information provided, and on use of PACT Catalogue data. The second study was a questionnaire survey of the 1047 practices in the West Midlands region in which GPs were asked how they used PACT data. Analysis of the interviews showed that GPs' views on the Standard Report varied widely although most found it helpful. Many GPs used the data in a limited way and only used a small part of them. Single-handed GPs and small practices were least likely to make use of PACT data and few practices analysed the data in any depth. Most respondents said that comparing their costs with health authority and national averages was useful for considering where to make changes in their prescribing. GPs indicated they would like the report to include some interpretation of the data with suggestions for changes which could be made. The regional survey confirmed that PACT Standard Reports are only used in a limited way and how they are used varies with practice size. We conclude that PACT Standard Reports were rarely used to analyse prescribing in any depth and GPs need more support in making better use of the data.