It is not known if the risk factors for hospital utilization are similar to the risk factors for mortality in chronic dialysis patients. The risk factors associated with hospital days per year of patient risk were identified in a subset of patients in Network 6 (the states of North Carolina, South Carolina, and Georgia) who began dialysis in 1989. The demographic characteristics of this cohort of 1572 patients included a mean (+/- SD) age of 57.4 +/- 15.0 yr; 63.7% of the patients were African American, 52.4% were female, and 33.0% had diabetes mellitus as the primary cause of ESRD. The median number of hospital days per year of patient risk was 8.8, with 25th and 75th quartiles of 3.9 and 20.1, respectively. By using multiple regression analysis, the strongest predictors of the number of hospital days per year of patient risk included low serum albumin level (P = 0.0001), decreased activity level (P = 0.0006), diabetes mellitus as the primary cause of ESRD (P = 0.002), peripheral vascular disease (P = 0.004), white race (P = 0.01), increasing age (P = 0.03), the absence of hypertension (P = 0.03), and the presence of angina (P = 0.03), smoking (P = 0.03), and congestive heart failure (P = 0.045). These risk factors are similar to those reported for an increased risk of mortality in dialysis patients and some of them, such as smoking, are modifiable and may be amenable to interventional strategies.