Context: The concept of standard therapeutic guidelines is relatively new in the primary health care setting in India. Objective: To develop standard therapeutic guidelines for selected common diseases for the primary health care centres (PHCs) of a South Indian district and to evaluate medical officers' perceptions about the proposed guidelines and about guidelines in general. Method: A questionnaire survey of medical officers was conducted to collect data on the most commonly-presenting diseases and doctors' treatment choices in PHCs in Mysore. Draft guidelines were developed for these conditions based on available literature, together with microbiological sensitivity data from the three district hospitals. User feedback on the draft guidelines and on guidelines in general was obtained from medical officers using a postal questionnaire. Setting: Sample of 17 of the 93 PHCs in Mysore. Key findings: Upper respiratory tract infection was the most commonly-presenting condition. Procaine penicillin was the most commonly-used drug and there were examples of inappropriate treatment choices. The survey produced evidence that access to medicines on the government's "essential" list was not uniform, with many patients having to purchase prescribed drugs that were not on the list. The response rate to the user feedback questionnaire was 62 per cent (31 doctors). The medical officers had positive opinions about guidelines in general and felt that the guidelines we proposed were useful and would help them to improve their prescribing habits. Conclusions: Prescribing in primary care in India needs to be improved. The involvement of potential users of the guidelines in their development should increase their acceptability and thus their use in practice.