In view of the effect of $eta_2$-Adrenergic receptors ($eta_2$-AR) as a risk factor for essential hypertension, we investigated the Fnu4HI and MnlI RFLPs of $eta_2$ -AR gene in the Korean patients with essential hypertension and normal controls. There were no significant differences in the allele and genotype of these polymorphisms between normotensive and essential hypertensive subjects. In ethnic comparison, the allele frequencies of these three sites contained Nde I RFLP reported the association with essential hypertension in Korean population previously, were very different from those of other ethnic populations studied. The significant linkage disequilibrium was detected only in hypertensive group between Nde I and Fnu4HI sites. The Fnu4HI RFLP was also significantly associated with plasma triglyceride (TG) level. Therefore, our results suggest that the significant association between Fnu4HI variation in the human $eta_2$-AR gene and plasma TG level may reflect the potential role of human $eta_2$-AR gene as one of the genetic components for cardiovascular risk.