Glycemic control in diabetic patients was evaluated by HbA1c determined in annual health checkups in employees of an electrical component manufacturer of 14, 073 empoloyees, aged over 40 years, 498 were judged of “need treatment for diabetes medically” in 1997.A questionnaire was given to the subjects in 1999 to evaluate medical care in 1998 (response rate 88%).Some 81% answered that they were under going regular medical care.Those without medical care and diabetic subjects who did not respond to the questionnaire showed higher HbA1c (7.6±1.5% and 8.1±2.1) than those with medical care (7.5±1.5).The reasons for discontinuation of regular medical care were mostly “personal.” HbAic was similar in different types of medical facilities (i.e.outpatient clinics of general hospitals and other types of hospital, clinics of practitioners, and clinics at the place of work).Glycemic control did not significantly differ in relation to the presence of diabetes specialists registered by the Japan Diabetes Society.Patients under medical care in outpatient clinics of general hospitals and clinics with diabetologists were more frequently treated with insulin.Foot examination was poorly done, but relatively well done in the clinics with the specialists, suggesting that glycemic control of diabetic subjects is insufficient at in most medical facilities for the prevention of diabetic complications. Guidelines for diabetes treatments should therefore be used by the general practitioner to ensure better clinical care for diabetic patients.