1. Essential hypertension is a complex polygenic disorder, the pathogenesis of which is dependent on an interplay between genetic and environmental factors. Various studies suggest an association between beta(1)-adrenoceptor gene polymorphisms (Ser49Gly and Arg389Gly) and cardiovascular disorders, including hypertension, cardiomyopathy and congestive heart failure. 2. The genetic profile of the beta(1)-adrenoceptor gene has not yet been documented for any Indian population. Thus, the aim of the present study was to investigate the association between beta(1)-adrenoceptor gene polymorphisms and essential hypertension in a south Indian Tamil population. 3. The present case-control study included 438 patients with essential hypertensives and 444 healthy volunteers from the Tamil population. Genotyping was performed using real-time polymerase chain reaction. 4. Genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism were compared between hypertensive patients and healthy volunteers. The homozygous variant genotype Gly49Gly of the Ser49Gly polymorphism was higher in hypertensive patients compared with controls (12.3 vs 7.4%, respectively). After adjusting for confounding variables (odds ratio (OR) 2.0; 95% confidence interval (CI) 1.2-2.9; P < 0.01) by multilogistic regression analysis, the gene was found to be associated with hypertension. A significant interaction was observed in hypertensive patients carrying the Ser49Gly/Gly49Gly x Arg389Gly/Gly389Gly genotypes (OR 1.9; 95% CI 1.1 2.7). 5. In conclusion, the Ser49Gly polymorphism is associated with essential hypertension in a south Indian Tamil population. The results of the present study deviate from those of previous studies, implying that marked interethnic difference exist in beta(1)-adrenoceptor gene polymorphisms.