Snake venom is a complex biological fluid consisting mainly of proteins and peptides possessing diverse biological activities. Snake venoms draw attention due to their bioactive proteins/peptides with therapeutic and diagnostic potential. Testing the stability of snake venom proteins under different conditions including temperature provides useful data for venom research. Macrovipera lebetinus, blunt-nosed viper, is the biggest viper species of Türkiye distributed mainly in eastern and southeastern Anatolia. Although its venom components were investigated before, there is limited data regarding the effect of temperature on its venom proteins. The present study aimed to investigate the effect of temperature on the venom proteins of M. lebetinus. For this purpose, venom samples were incubated at 25, 37, and 50°C. Thereafter, venom proteins were separated by two-dimensional gel electrophoresis (2D-PAGE) method. Some qualitative and quantitative differences in the protein profile indicating structural changes and degradation were observed especially after 50°C treatment. It has been found that the protein spots most affected by temperature will most likely contain metalloproteinase, phospholipase A2 and ʟ-amino acid oxidase enzymes, by comparing the experimental molecular weight and pI values with those in the literature. Detailed studies including enzyme activities and toxicity assays will provide more data on the stability of M. lebetinus venom under different conditions.