A case-control study was conducted to determine factors involved in foot ulceration in Thai non-insulin-dependent (Type 2) diabetic patients. Fifty-five patients with foot ulcers (42 females and 13 males) and 110 patients without foot ulcers (83 females and 27 males) were evaluated for 26 factors possibly associated with foot ulceration. The results showed that diabetic patients with foot ulcers had significantly lower diabetic knowledge and foot-care practice scores; poorer glycaemic control, renal function, and visual function, and higher prevalence of retinopathy and peripheral neuropathy than diabetic patients without foot ulcers, whereas there were no differences in peripheral vascular status between both groups, each having a low prevalence. Multiple logistic regression analyses indicated that the risk of developing foot ulcers was associated with only three factors which were peripheral nerve status as determined by somatosensory evoked potentials (OR = 1.67; 95% CI 0.31 -8.97), visual acuity (OR = 0.223 per unit decrease in decimal visual acuity; 95% CI = 0.005, 0.39) and fasting plasma glucose level (OR = 1.01 per mmol l-1 increase; 95% CI = 1.00, 1.02). We conclude that peripheral neuropathy, visual impairment, and poor glycaemic control, but not peripheral vascular insufficiency, are the major independent risk factors associated with foot ulceration in Thai diabetic patients.