Lentil is the second major Rabi sown legume after chickpea, which is grown in winter season. The productivity of lentil in India is 730 kg/ha and in Uttar Pradesh is 891 kg/ha. One of the major constraints in cultivation of existing lentil varieties is low productivity and poor management practices. It appears due to non-adoption of recommended high yielding varieties and advance technologies by the farming community in the Eastern Plains of Uttar Pradesh. Frontline demonstrations (FLDs) programme is an effective technology transfer tool for better technology adoption that bridges the yield gaps. The technological extension yield gaps in lentil were carried out for 3 years during 2013-14 to 2015–2016 under an FLD programme in rice-lentil cropping system in hot sub-humid (moist) ecoregion of India, revealing that due to technological extension yield gaps, there was a large yield gap between potential demonstration yields. To replace this anomalous, we had conducted 62 FLDs at farmer fields of various adopted villages by the Krishi Vigyan Kendra (KVK), Deoria under ICAR-Indian Institute of Vegetable Research, Varanasi, Uttar Pradesh. Cultivation practices comprised under FLD viz. improved varieties, irrigation, date of sowing, seed treatment, spacing, balance use of fertilizers, intercultural operations and plant protection measures showed increase in yield of lentil varieties from 10.18-35.57% over local checks. Technology gap was highest in HUL 57 (754 kg/ha) and lowest in L 4147 (520 kg/ha). The analysis of data for extension gap showed that L 4147had the highest gap (290 kg/ha) and Pusa L4076 had the lowest gap (110 kg/ha). Technology index was highest (41.8%) in HUL 57 and lowest (20.8 %) in L4147.The lower the value of the technology index indicates the more feasibly of the technology in Eastern Plains of Uttar Pradesh.