Abstract: OBJECTIVE: To find the characteristics and prevalence of nailfold capillary changes in a large series of patients with BD, and to analyze their possible relation to other clinical characteristics of the disease. MATERIALS AND METHODS: We performed nailfold capillaroscopy in 128 randomly selected patients fulfilling International Classification criteria for BD. Capillaroscopy was done in 8 fingers with a 3.2x microscopy. All patients were questioned for the history of Raynaud phenomenon, ischemic ulcers, smoking and hypertension. A computerized form including demographic, clinical and paraclinical features was used to collect data. Univariate and multivariate logistic regression were used to analyze the relation between capillaroscopic findings and disease characteristics. Odds ratio (OD) and a confidence interval at 95% (CI) were calculated for each item. RESULTS: The mean age of the patients was 37±10 years, and the male to female ratio was 1.56/1. Capillaroscopy was abnormal in 51 patients (40%, CI:8.5). Enlarged capillaries were seen in 33 patients (26%, CI:7.6), hemorrhages in 21 (16%, CI:6.4) and capillary loss only in 1 patient. In univariate logistic regression analysis, the presence of enlarged capillaries was associated with lower age at disease onset (OR=0.9, CI:0.9-1; p=0.04), hypertension (OR=4.2, CI:1.5-11.4; p=0.006), superficial phlebitis (OR=5.5, CI:1.2-24.4; p=0.03) and negative pathergy test (OR=0.4, CI:0.2-0.9; p=0.04). The presence of hemorrhages tended to be associated with articular symptoms (p=0.05). Multivariate analysis also confirmed the association of enlarged capillaries with lower age at disease onset (p=0.01), hypertension (p=0.001) and superficial phlebitis (p=0.03). CONCLUSIONS: Nailfold abnormalities, mainly enlarged capillaries, are frequent in patients with BD. Our results suggest these abnormalities may be related to other vascular features of the disease such as superficial phlebitis, but it does not seem to confer special risk for any other specific clinical symptom of the disease. Key words: Behcet's disease, nailfold capillaroscopy, microcirculation, superficial phlebitis