Background/Aim: Proton pump inhibitor (PPI) prescribing is costly. The volume of PPI prescription is also increasing, despite little evidence that would justify the increase. General practitioners (GPs) are largely responsible for PPI prescribing, yet knowledge of their views concerning PPIs which might explain the apparent anomaly of prescribing costly drugs without justification is lacking. The aim of this study is therefore to investigate how GPs make decisions about PPI prescribing. Method: Qualitative study design using focus groups of 34 GPs and 15 training GPs analysed according to grounded theory principles and use of constant comparative analysis. Results:The participants showed agreement about the clinical factors potentially relevant to PPI prescribing such as age of presentation and endoscopy, issues of Helicobacter pylori eradication and issues around malignancy. There was considerable controversy, however, as to how to apply those factors in real clinical consultations. GPs in training and academic GPs tended to be more conservative; service-based GPs more pragmatic. There was agreement about the need to review long-term PPI medication, but controversy about whether the conventional ‘step-up step-down’ approach was realistic in practice. Good agreement was apparent about the effectiveness, the cost implications, and some of the ethical issues surrounding PPIs, but considerable controversy as to how far such factors should influence prescribing of PPIs. Conclusion:The GPs showed good understanding and knowledge of the issues surrounding PPI prescribing. There was considerable controversy as to how such knowledge should be translated into practice.