We systematically inspected insulin injection sites in 100 insulin-requiring patients attending the Diabetic Clinic of the Tikur Anbassa Hospital (TAH) in order to identify local complications related to incorrect injection technique: local complications were found in 53 cases: skin hyperpigmentation and/or indurations in 30 patients; and fat atrophy or hypertrophy in 31 patients. Illiteracy was significantly more common among those with local complications (18/53 versus 6/47, chi 2 5.03, P < 0.05). Mean fasting blood glucose on the day of the inspection was significantly higher (14.9 + 6.3 mmol/l versus 10.5 + 6.1 mmol/l, P < 0.001) and a fasting blood glucose > 10 mmol/l more common (41/53 versus 20/47, chi 2 14.1, P < 0.0005) in those with than in those without local complications. There was no significant difference between the two groups in mean duration of diabetes (6.9 + 5.6 years versus 6.6 + 5.8 years), frequency of hypoglycaemic episodes (12/53 versus 5/47, chi 2 1.76, P > 0.05) or mean daily insulin dose (44 + 18 units versus 44 + 22 units per day). Therefore, we concluded that local complications resulting from incorrect injection technique, a common finding in the group of patients studied, may be common among insulin requiring diabetic patients in general. Incorrect insulin injection causes local complications and disfigurement which may compromise compliance. Furthermore, insulin absorption tends to be erratic from intradermal and fat hypertrophy sites thus interfering with effective diabetic control. Insulin injection sites should be inspected routinely to detect and correct family technique promptly.