This paper discusses the existence of phonological and lexical isoglosses in Tilung (Rai) and other Kiranti groups on the basis of the scanty materials available, which are some 140 words and other morphemes extracted from one article written by Sueyoshi Toba (2004) and a book written by Lal Rapaca (2006). The Tilung data were compared with language data from various other Kiranti languages and reconstructed Proto-Kiranti etyma. More than half of the collected Tilung words and other morphemes could be assigned to particular cognate groups. These groups illustrate the various phonological developments that have taken place in Tilung and mark important lexical isoglosses in Kiranti. It is shown that, with respect to development of initial obstruents, Tilung is remarkably similar to the Western Kiranti language Thulung. The shared phonological developments may perhaps have taken place at a time when pre-Tilung and pre-Thulung were spoken in a contiguous area. From a lexical view point, though, Tilung shares more etyma with Central and Eastern Kiranti languages than it does with Western Kiranti. The data presented support Hanßon’s (1991) claim that Tilung may well be a marginal member of Western Kiranti, since it shares a unique phonological isogloss with Thulung, but also confirms Toba’s (2004) report that Tilung is lexically more close to Central and Eastern Kiranti.