CCL15 exerts biological effects on a variety of cells, including monocytes. NF-kappaB has been reported to be involved in the transcription of the CCL15 gene. In this study, we have identified an AP-1 element located at -76/-65, which appears to regulate the transcription of the CCL15 gene. We also confirmed that the AP-1 factor binds to the element. Specific inhibitors for MAPK pathways and expression of dominant negative MKK4 or JNK1 reduced PMA-induced transcriptional activation of CCL15. Our findings indicate that transcription of the CCL15 gene is regulated by AP-1 and NF-kappaB through MEK and JNK MAPK pathways in monocytoid cells.