The heat tolerance of 44 WorldVeg accessions of Lablab purpureus at vegetative stage from WorldVeg gene bank was examined in terms of high cell membrane stability and chlorophyll fluorescence as two heat-stress tolerant traits at vegetative stage. Relative injury index, is a parameter, which reflects cell membrane stability. All accessions with an injury index below 50% were selected as promising for this trait. The photosynthetic efficiency ratio is a parameter, which reflects chlorophyll fluorescence. All accessions with an injury index above 35% were selected as promising for this trait. Six accession were considered as heat tolerant accession. However, no correlation was found between relative injury index and photosynthesis efficiency ratio.