This paper presents early evaluation results of A Kaleidoscope of Care, a cross-disciplinary curriculum in HIV and substance use, designed to train HIV health care and substance abuse treatment professionals in providing better care to the clients they share in common. The curriculum applies adult learning principles to engage diverse professionals in building skills to promote health and adherence, engagement and retention in care, harm reduction, and interdisciplinary collaboration. Early evaluation of the curriculum indicates that it has enhanced knowledge and built skills in serving HIV-infected substance users among providers from multiple disciplines