This report describes the identification of a cDNA encoding STK13, a third human protein kinase related to the Drosophila Aurora and the budding yeast Ipl1 kinases. After screening of a human placental cDNA library with a Xenopus laevis cDNA encoding the pEg2 protein kinase and 5' RACE on testis mRNA, a full-length cDNA was isolated. The chromosomal localization of STK13 on 19q13.3-ter between the markers D19S210 and D19S218 was established by a combination of somatic cell and radiation hybrid panel PCR screening. The localization of STK13 on human chromosome 19 was confirmed by fluorescence in situ hybridization (FISH) using a genomic clone containing STK13 as a probe.