Aim To investigate whether individuals with essential hypertension have increased cytokines, specifically interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α), secretion in peripheral blood mononuclear cell (PBMC). Methods In a cross-sectional study involving 12 apparently healthy control and 33 patients with essential hypertension, concentrations of IL-1β and TNF-αwere compared in PBMC culture supernatant. PBMC were isolated by gradient centrifugation. IL-1βand TNF-αconcentrations in supernatant from PBMC were measured by enzyme-linked immunosorbent assay(ELISA). Results There is no difference in the spontaneous secretion of IL-1β(182±66 ng/L vs 154±63 ng/L, p<0.05) and TNF-α(142±74 ng/L vs 168±61 ng/L )by PBMC between normal control and hypertensive patients. After stimulation by lipopolysaccharide, both IL-1β(2 179±660 ng/L vs 182±66 ng/L, p<0.05; 154±63 ng/L vs 2 854±631 ng/L) and TNF-α(442±134 ng/L vs 142±74 ng/L; 500±176 ng/L vs 168±61 ng/L, p<0.05) secretion by PBMC increased dramatically compared with the spontaneous secretion. After stimulation by lipopolysaccharide, patients had increased IL-1β(2 179±660 ng/L vs 2 854±631 ng/L; p< 0.05 ) secretion by PBMC compared with controls. Conclusions These data suggest that PBMC in patients with essential hypertension are preactived and inflammation mechanism may be involved in the pathogenesis of hypertensive disease.