This study was performed to investigate the potential relationship between left ventricular hypertrophy (LVH) and proinflammatory cytokines in hemodialysis (HD) patients and the effect of HD on cytokine production. Serum interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) measurements and echocardiographic studies were performed in 35 stable HD patients. A variety of probable risk factors for LVH including age, HD duration, blood pressure (BP), body mass index, lipid profile, hemoglobin, albumin, parathormone and homocysteine levels were also investigated. Additionally, the effect of HD procedure on cytokine levels was evaluated. Predialysis serum levels of IL-1 beta, IL-6, TNF-alpha, and homocysteine in HD patients were compared with 12 healthy subjects. Left ventricular hypertrophy was demonstrated in 20 (57%) of HD patients by echocardiography. Left ventricular mass index (LVMI) was correlated positively with systolic BP (r=0.556, p=0.001), diastolic BP (r=0.474, p=0.004), and serum levels of TNF-alpha (r = 0.446, p = 0.009). Multiple regression analysis showed that systolic BP and TNF-alpha levels were significant independent predictors of LVH. No relationship was observed between LVH and other parameters. The mean predialysis serum level of IL-6 was significantly higher in HD patients compared to healthy controls (15.7 +/- 8.7 vs. 7.3 +/- 0.7 pg/ mL, p=0.001). Predialysis serum levels of TNF-alpha in HD patients were higher when compared to healthy subjects, but the difference was not statistically significant (8.3 +/- 3 vs. 7 +/- 1.45 pg/mL, respectively, p>0.05). However, serum levels of IL-6 and TNF-alpha significantly elevated after HD, when compared to predialysis levels (from 15.7 +/- 8.7 to 17.8 +/- 9.5 pg/mL, p = 0.001 and from 8.3 +/- 3.0 to 9.9 +/- 3.5 pg/mL p=0.004, respectively). As a conclusion, in addition to BP, proinflammatory cytokines, TNF-alpha in particular, seem to be associated with LVH in ESRD patients.