Exercise and diet are the cornerstones of management of non-insulin-dependent diabetes mellitus (NIDDM). Many older people have difficulty in exercising, missing benefits on glycaemic control, weight, cardiac disease and mood. We report the outcomes of a 6 month structured exercise and support programme based on a health promotion model, on physical activity, glycaemic control and parameters of cardiovascular risk in non-exercisers, compared with standard outpatient clinic education. A total of 26 non-exercising patients were randomised to an intervention or control group (ten men, 16 women; mean age (+/- S.D.) 60 +/- 8 years). Programme participation was not associated with any significant increase in activity. Glycated hemoglobin (HbAtc) levels tended to stabilise in the intervention group during the 6 month programme and to deteriorate in the control group (P = 0.03); by 12 months HbA1C levels deteriorated to a similar level in both. Programme participation did not cause significant change in anthropometric or metabolic parameters. Examining the cohort as a whole, increased activity over 6 months was associated with improvements in weight, body mass index (BMI), body fat and fasting insulin. Activity increases over 12 months were associated with improvements in weight and BMI. These changes could not be attributed to changes in energy intake or dietary composition. We conclude that while exercise can benefit older people with NIDDM, a programme based on a model of health promotion was not effective in increasing physical activity.