A 1.8 kb human cDNA probe for angiotensinogen (renin substrate) was used to determine the chromosomal location of the angiotensinogen gene by in situ hybridization. The results show that human chromosome region 1q4 contains the angiotensinogen gene. The human renin gene has also recently been assigned to the same band of chromosome 1. Thus, the angiotensinogen and renin genes are located in the same region of chromosome 1.