Neither the sociodemographic correlates nor the biochemical/clinical consequences of missed dialysis treatments have been well defined. During a 10 week period, the authors enumerated missed dialysis treatments among 430 patients randomly selected from a pool of 1,395 hemodialysis patients. A forward logistic regression model was used to determine whether a relationship existed between missed dialysis treatments and the following independent variables: age, gender, race, renal diagnosis, length of time on maintenance hemodialysis, co-morbidity index, modified Karnofsky score, employment status, household residents, and laboratory indices. Forty-three (10%) of 430 patients missed a total of 96 treatments. Despite equivalent treatment with erythropoietin, patients who missed dialysis treatment(s) had a lower mean hematocrit (27 +/- 4.3%) at the end of the study than those patients who underwent all treatments (29 +/- 4.5%) (p = 0.0287). Mean serum albumin and creatinine levels were equivalent in compliant and noncompliant patients. Recent starts (p = 0.0048), and younger patients (p = 0.0424) were most likely to miss dialysis treatment(s). One of the major consequences of missed dialysis treatment(s) is exacerbation of anemia, and younger patients and freshly started patients are more likely to miss scheduled dialysis treatments than their respective counterparts.