An attempt was made out to study the distribution and diversity of gelatinous zooplankton in the South Eastern Arabian Sea in the region Kanyakumari to off Kollam. A total of 19 species belonging to 8 groups such as chaetognaths, siphonophores, Hydrozoa and Scyphozoa of the phylum Cnidaria, ctenophores, appendicularians, doliolids and salps were recorded. Chaetognaths were not only predominant group, but also the most numerous. Sagitta enfl ata was the most widely distributed chaetognath species from most of the stations studied. Th e siphonophores were the second most abundant group. Shannon-Weaver species diversity index (H′), Margalef’s species diversity index (D) and Pielou’s species evenness (J′) of gelatinous zooplankton were found to be higher from the off shore, Kollam (Station 10) and minimum from the inshore, the Kanyakumari (Cape) West (Station 1). Diversity of gelatinous zooplankton was found to be positively correlated with atmospheric temperature, sea surface temperature and pH. A continuous seasonal study should be conducted to understand the clear impact of physical and chemical factors on the distribution and diversity of gelatinous zooplankton along this region.