BACKGROUND: We wanted to identify differences between diabetic patients who smoke and those who do not smoke to design more effective strategies to improve their diabetes care and encourage smoking cessation. METHODS: A random sample of adult health plan members with diabetes were mailed a survey questionnaire, with telephone follow-up, asking about their attitudes and behaviors regarding diabetes care and smoking. Among the 1,352 respondents (response rate 82.4%), we found 188 current smokers whose answers we compared with those of 1,264 nonsmokers, with statistical adjustment for demographic characteristics and duration of diabetes. RESULTS: Smokers with diabetes were more likely to report fair or poor health (odds ratio [OR] = 1.5, P = .03) and often feeling depressed (OR = 1.7, P = .004). Relative to nonsmokers, smokers had lower rates of checking blood glucose levels, were less physically active, and had fewer diabetes care visits, glycated hemoglobin (A1c) tests, foot examinations, eye examinations, and dental checkups (P < or = .01). Smokers also reported receiving and desiring less support from family and friends for specific diabetic self-management activities and had lower readiness to quit smoking than has been observed in other population groups. CONCLUSIONS: Clinicians should be aware that diabetic patients who smoke are more likely to report often feeling depressed and, even after adjusting for depression, are less likely to be active in self-care or to comply with diabetes care recommendations. Diabetic patients who smoke are special clinical challenges and are likely to require more creative and consistent clinical interventions and support.