Glucocorticoid receptor, encoded by NR3C1, is a transcriptional regulator of many drug metabolizing enzymes and anti-inflammatory molecules. In order to identify genetic variations of the NR3C1 gene, genomic DNA from 265 Japanese individuals was sequenced. Fifty genetic polymorphisms were identified, including 32 novel ones [3 were in coding exons, 17 in the introns, 4 in the 5'-untranslated region (UTR), and 8 in the 5'-flanking region]. The novel nonsynonymous variation was 420G>T (Lys140Asn), and the allele frequency was 0.004. We did not detect any nonsynonymous polymorphism reported previously in other races, including a relatively frequent SNP Asn363Ser found in Caucasians and African-Americans. Thus, ethnic differences between Japanese and other races are suggested to exist in NR3C1.