The management approach to non-insulin-dependent diabetes mellitus among family doctors in Hong Kong was studied using two case histories. In 1996, all 804 fellows, members and associate members of the Hong Kong College of Family Physicians were sent a letter and a questionnaire. Of the 512 who responded, 405 were male and 95 were female (12 were discarded) with ages ranging from 24 to 77 years (median 40). For the 48-year-old obese man who showed improvements in blood glucose and symptoms after diet for 6 weeks (Case 1), most respondents suggested adding a sulphonylurea (39.0%) or metformin (21.1%), or continuing diet (35.2%). Younger and more junior doctors tended to use metformin plus diet. Of 192 respondents who wanted to use a sulphonylurea, gliclazide (45.8%) and glibenclamide (42.7%) were chosen most often. For the 76-year-old overweight woman with symptomatic diabetes despite diet therapy (Case 2), most respondents suggested adding a sulphonylurea (41.9%), metformin (25.6%) or both (19.2%). Younger and more junior doctors tended to use metformin plus diet, whereas older doctors tended to use insulin plus diet. Older and more experienced doctors tended to use diet plus metformin and sulphonylurea. Of 208 respondents who wanted to use a sulphonylurea, gliclazide (47.8%) and glibenclamide (30.1%) were chosen most often. The management approach to NIDDM varied with the age and experience of the doctor.