The technological gap between existing and recommended technologies of green gram crop was studied during 2018, 2019 and 2020. During the study period a total of 150 Front Line Demonstrations (FLDs) were conducted on farmers’ fields in Salipery, Vaduvur, Radhanallur, Alangudi and Needamangalam villages of Thiruvarur district. The findings of the study revealed that the improved technology recorded a mean yield of 9.73 q/ha which was 31.47 % higher than that obtained with farmers practice (7.29 q/ha). The study exhibited mean extension gap of 1.95 q/ha, technology gap of 2.57 q/ha and with mean technology index of 20.88 per cent. An additional investment of Rs. 2091/ha coupled with Yellow Mosaic Virus (YMV) resistant varieties, seed treatment with bioagents, recommended seed rate and need based plant protection measures resulted in additional mean returns of Rs. 14227/ha. Hence, higher effective gain of Rs. 12135/ha with incremental benefit cost ratio of 6.76 was obtained with improved technologies.