Evidence-based guidance recommends that primary care health practitioners should deliver brief interventions to their patients to change behaviours to reduce overweight and obesity. This cross-sectional study investigates UK general practitioners' (GPs) and practice nurses' communication about overweight with their overweight and obese patients. Forty general practitioners and 47 practice nurses in two inner-London primary care organizations completed a questionnaire about past practice and concerns. When there was no identified medical problem, 38% of GPs and 14% of practice nurses reported raising the issue on less than 50% of occasions. Practice nurses were more likely than GPs to raise the issue of weight, both when there was no medical problem and when there was a medical problem. When they did raise the issue of overweight, only 9% did so in the context of presenting possible solutions to weight loss or in discussions about health promotion. Fifty two per cent of GPs and 28% of practice nurses had concerns about raising the issue of overweight; the most common being that patients would react emotionally to the message. These results suggest that there is considerable room for improvement in the frequency with which primary care practitioners address the questions of weight in their overweight patients, especially amongst doctors. Training to increase skills and confidence in communicating about weight is recommended.