Our objective was to study the relationship between plasma levels of TNF-α, IL-1β, sIL-2R and disease activity in ulcerative colitis. Serum TNF- α, IL-1β and sIL-2R concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in 20 healthy subjects and 44 patients with active ulcerative colitis (UC). Patients were assessed by the ulcerative colitis activity index (UCAI), criteria previously established. Serum TNF-α levels were found to be 7.33 ± 8.21 pg/mL in the control group, 22.40 ± 22.34 pg/ml in patients with UC. The serum sIL-2R levels obtained were 459.3 ± 168.8 U/ml in the control group and 1375.5 ± 525.1 U/ml in patients with UC. Serum IL-1b levels were 1.02 ± 0.24 pg/ml in the control group and 8.92 ± 5.88 pg/mL in patients with UC. TNF-α, IL-1β and sIL-2R levels were significantly higher in the UC group than those observed in the normal subjects (p<0.0001). There was significant correlation between UCAI with TNF- α (r=0.7351, p<0.05), IL-1β (r=0.7253, p<0.05) and sIL-2R (r=8497, p<0.05) serum levels. These results suggest that TNF-α, IL-1β and sIL-2R levels are related with activity of these disease and measurement of cytokine serum concentrations may provide a simple way to monitor disease activity in UC.