Possession-mediumship, the expected possession of a specialist by a spirit for the purpose of soliciting knowledge and assistance, is a form of divination which occupies an important place in the ethnomedical traditions of village South Asia. This article examines the institution and practitioners of possession-mediumship in the vicinity of a Jalari (Telugu fishing caste) village in coastal southeastern India. The practitioners include two Jalari women and two non-Jalari men. All four practice on behalf of Jalari patients. Although they employ similar diagnostic repertoires and mediumistic techniques, they vary considerably in their recruitment to and experience of possession-mediumship. Following a description of divinatory practices, the analysis focuses on ambivalence in the motherson relationship, arguing that, in some circumstances, its resolution may encourage development as a possession-medium.