To study how clinical characteristics influence the risk of peritonitis in African American patients with end-stage renal disease treated with continuous ambulatory peritoneal dialysis (CAPD), we examined the risk of developing a first episode of peritonitis among 1,595 new dialysis patients initially treated by CAPD over a two year period in North Carolina, South Carolina, and Georgia (Network 6). Characteristics examined were demographic and socioeconomic factors, functional status, serum albumin and comorbid conditions. There were 538 initial episodes of peritonitis during an average of 8.8 patient months of follow-up; the time to peritonitis for the entire cohort was 26 months. Factors found to be independently associated with a risk for peritonitis were student status (Odds Ratio and 95% Confidence Interval = 2.4; 1.4 to 4.3), rental housing (1.2; 1.0 to 1.5), and substance abuse (1.9; 1.1 to 3.2). African Americans were 60% more likely to have an initial episode of peritonitis during follow-up than whites (1.6; 1.3 to 1.8). The time to the initial episode was 21 months for African Americans versus 32 months for whites (P < 0.001). Even after adjusting for other factors, African Americans were significantly more likely to develop peritonitis (1.5; 1.2 to 1.8). Thus, the increased risk of peritonitis of African American patients treated by CAPD is independent of other demographic, socioeconomic and comorbid characteristics.