In 1981 the Rehabilitation Centre Laab (A-2381 Laab im Walde, Austria) had admitted a total of 1149 patients. These included 968 patients with diabetes mellitus (431 male, 537 female), of whom 428 (44.21 percent) had been insulin-dependent (IDDM) and 540 (55.79 percent) non-insulin-dependent (NIDDM). The mean blood glucose (MBG) levels present at the time of admission indicated that glycemic control was better in patients with IDDM than those with NIDDM. The poorest glycemic control was encountered in NIDDM of (A) age 31-40 (MBG = 187 mg/dl) and (B) over age 70 (MBG = 194 mg/dl); it had been possible in these patients to lower MBG to (A) 138 mg/dl and (B) 147 mg/dl. Juvenile IDDM patients (under age 30) had poorer glycemic control (MBG = 190 mg/dl) than the older IDDM patients (MBG = 181 mg/dl), and therapeutic success was greater in the latter group. Concluding from the glycohaemoglobin changes found, improvements in glycemic control were achieved in 35.32 percent (IDDM: 15.39 percent; NIDDM: 19.93 percent); in 62.08 percent (IDDM: 26.65 percent; NIDDM: 35.43 percent) it had remained unchanged, and had deteriorated in 2.16 percent (IDDM: 1.75 percent; NIDDM: 0.41 percent). For 13 patients treated so far by diet alone, oral medication had to be started; 2 patients (0.2 percent) required immediate introduction of insulin. In 126 patients (12.9 percent) on oral medication, insulin therapy had to be initiated, whereas in 32 cases (3.3 percent) oral medication was discontinued in favour of purely dietetic control.