The objective of the study was to determine the level of beta2-microglobulin (beta2-m) in hemodialysis (HD) patients and the factors affecting it. This cross sectional, hospital based study was conducted between September and December 2008 at the Hemodialysis unit of Shalamar Hospital, Lahore. All patients with end-stage renal disease (ESRD) who were on maintenance HD for more than three months were included in the study. Patients with acute renal failure and on dialysis for less than three months were excluded. Demographic data were collected and details of dialysis (type of dialyzers, dialysate bath, membrane used) were recorded. Blood samples of the patients were drawn for hematological (hemoglobin, hematocrit), biochemical (urea, creatinine, uric acid, albumin) and beta2-m level measurement. The total number of patients studied was 50. The major causes of ESRD included diabetes mellitus and hypertension seen in 37 (74%) and 10 patients (20%), respectively. The beta2-m levels were significantly elevated in the study patients; 92.6 +/- 17.1 mg/L with a range of 54 to 130 mg/L as compared to 2.0 +/- 1.29 mg/L in the control group. The patients' age had a statistically significant relationship with the beta2-m level. The major reason for increased beta2-m level was use of low-flux dialyzers. Synthetic polysulphone membrane, bicarbonate, ultra pure dialysate and duration on HD were not asso-ciated with high beta2-m levels. Also, we found an inverse relationship between beta2-m levels and serum albumin of the study patients. Our study suggests that the beta2-m levels are significantly high in dialysis patients. Use of low-flux dialyzer seems to be the major reason for the high beta2-m levels. Age and albumin have statistically significant relationship with beta2-m levels.