The dopamine receptor type 1 (DRD1) has been implicated in the development of hypertension in humans as well as in animal models of spontaneous hypertension. We screened the entire coding and promoter region of the human DRD1 receptor for polymorphisms to analyze their association with hypertension. The allele frequencies of two common single-nucleotide polymorphisms, A-48G and G-94A were determined in 493 hypertensive patients and 209 normotensive controls. Allele frequencies did not differ for both polymorphisms between the two groups (-48 G-allele in hypertension = 0.37; -48 G-allele in normotension = 0.36; -94 A-allele in hypertension = 0.14; -94 A-allele in normotension = 0.10). Our findings in these Caucasian patients are in contrast to a recent Japanese study that revealed a significant association of the -48 G-allele with hypertension. Thus, racial differences may play an important role concerning the association of variants in the dopamine receptor type 1 gene with essential hypertension.