The present invention provides polynucleotides and polypeptides of a human sphingosine-1-phosphate phosphatase, referred to herein as hSPP1. The polynucleotides and polypeptides are used to further provide expression vectors, host cells comprising the vectors, probes and primers, antibodies against the hSPP1 protein and polypeptides thereof, assays for the presence or expression of hSPP1 and assays for the identification of compounds that interact with hSPP1.