This project provides an integrated proteomic and immunological dataset that documents inter‑ and intra‑population variation in venom composition for the forest‑steppe adder Vipera nikolskii and evaluates recognition by a commercial Vipera berus antivenom. The dataset includes label‑free LC–MS/MS raw data and identifications from 12 individual V. nikolskii venoms (two geographic populations, BG and KM), four pooled differently coloured reference samples (pooled V. berus; V. nikolskii white, yellow and mixed pooled venoms).