Field-pathological findings of 33 saiga antelope carcasses (adults and new-born) found in two sites (Tengiz and Turgai, Kazakhstan) during a mass die-off event in May 2015. In Kazakhstan May 2015, approximately 200,000 saiga antelopes died within a month-period causing a loss of two-thirds of the global population. The dramatic event occurred during calving season when females and young males stop migrating and form massive aggregations for calving purposes. With 100% morbidity and 100% mortality of affected herds observed, the 2015 die-off left the largest saiga population, Betpak-Dala, with approximately 30,000 survivors based on post mortality census, highlighting the imminent extinction threats to this critically endangered species. The lack of pathological investigations during historical mass mortality events has limited our understanding of disease-related mortalities in saiga antelope. Generally, aetiological agents were isolated from dead saiga, but the disease course and a full necropsy were not performed nor present in the records. However, for the first time, a full pathology report was possible during 2015. Full details about this dataset can be found at https://doi.org/10.5285/30cbfba7-f9a1-47d5-abdb-f2741041e487