Anticardiolipin (aCL) antibodies may play a role in the enhancement of platelet aggregation and/or progression of the macrovascular diabetic complications. Also, aCL antibodies may cause or promote ischemia and thrombosis. Therefore, we aimed to investigate IgG aCL and IgM aCL antibodies positivity in type 2 diabetic patients with and without ischemic diabetic foot. In this case-control study, we examined 40 diabetic patients without diabetic foot problem and 35 diabetic patients with ischemic diabetic foot. Forty diabetic patients (19 females, 21 males) without diabetic foot served as Group 1 and 35 diabetic patients (17 females, 18 males) who had ischemic diabetic foot served as Group 2. In the control group, 3 5 nondiabetic healthy subjects (18 females, 17 males) were included in Group 3. The groups were similar in age and sex, which is not statistically significant (P>.05). There was no difference in the IgG aCL antibodies positivity between Groups 1 and 3 (P>.05). However, IgG aCL antibodies positivity in Group 2 was significantly higher than those of the other groups (P<.05). IgG aCL antibodies were found positive in 10% (4/40) of Group 1, 34.3% (12/35) of Group 2 and 8.6% (3/35) of Group 3. When Groups 1 and 2 were compared, the odds ratio adjusted for age, gender, hypertension, coronary artery disease history, cigarette smoking, duration of diabetes mellitus, cholesterol, and haemoglobin A(1c) (HbA1c) was 6.8 [95% confidence interval (CI), 1.41-32.66; P=.016] for aCL positivity. In conclusion. although available evidence does not prove a causal association between positivity of aCL and diabetic foot, we believe that a causal association is supported by the data obtained from this study. (C) 2002 Elsevier Science Inc. All rights reserved.