A prospective, controlled, observer-masked study was conducted to investigate the suitability of contact lenses for patients with diabetes mellitus. Forty diabetic patients and 40 non-diabetic control subjects were fitted with soft hydrogel contact lenses to be worn on a daily wear basis for 12 months. The ocular response was assessed using slit lamp biomicroscopy, ultrasonic pachometry, corneal aesthesiometry and visual acuity measures. Compared to non-diabetic subjects, diabetic patients displayed significantly reduced corneal transparency, variable vision and reduced comfort with the contact lenses (p < 0.05). There were no significant differences between the two groups with respect to ocular hyperaemia, corneal staining, corneal thickness, corneal sensitivity or high contrast visual acuity. Contrary to previous reports, the response of the diabetic eye to contact lenses--as observed clinically--does not differ appreciably from that of the non-diabetic eye. These results suggest that current generation daily wear soft contact lenses can be a viable mode of vision correction for diabetic patients.