The Drosophila transient receptor potential (trp) gene and its homologue, trpl, have been suggested to mediate calcium entry during the insect's phototransduction process. We isolated a human cDNA, human trp‐1 (Htrp‐1), encoding a polypeptide of 793 amino acids that is 37% identical (62% similar) to Drosophila trp and trpl. Northern analysis showed that the Htrp‐1 transcript is approximately 5.5 kb and expressed in most human tissues, with higher amounts in ovary, testis, heart, and brain. Isolation of Htrp‐1 suggests that a trp‐type protein is present in mammals and should provide a useful tool in studying calcium‐depletion induced calcium influx processes.