The current investigation was designed to determine the total serum sialic acid (TSA), lipid associated sialic acid (LASA), total protein (TP), and TSA/TP values for 16 patients with active form of Behcet's disease, 12 patients with other uveitis types (pathologic controls) and 22 normal individuals. Data analysis indicated significant differences in mean TSA, LASA and TSA/TP values in patients with Behcet's disease (95.6 +/- 15.3 mg/dl, 29.8 +/- 7.4 mg/dl and 12.9 +/- 2.1 mg/g, respectively) and in pathologic controls (75.8 +/- 8.1 mg/dl, 26.6 +/- 0.3 mg/dl and 10.0 +/- 0.9 mg/g, respectively) when compared to normal controls (59.5 +/- 7.5 mg/dl, 19.2 +/- 3.2 mg/dl and 8.2 +/- 0.9 mg/g, respectively) (p < 0.01). No significant difference was observed in mean LASA values in patients with Behcet's disease when compared to pathologic controls (p > 0.05). No significant difference was observed in mean TP values in patients with Behcet's disease (7.4 +/- 0.7 g/dl), normal controls (7.3 +/- 0.4 g/dl) and pathologic controls (7.5 +/- 0.6 g/dl) (p > 0.05). A statistically significant difference was observed between the patients with Behcet's disease and pathologic controls with respect to TSA, TSA/TP values (p < 0.01). The results indicated that TSA and TSA/TP is most useful for differentiating Behcet's disease from other forms of uveitis.