This study presents foliar application effect of Kappaphycus alvarezii (5-15%) extract on yield and seed quality of greengram at flowering stage. Application of K. alvarezii (conc. 10.0%) significantly increased seed yield (30.11%) compared to control,due to increase in yield of pods, weight of pods as well as seed yield per plant and 100 seed weight. This treatment also improvednutritional quality of seed as follows: protein, 19.43; carbohydrate, 5.17; P, 3.61; and Mo, 52.63%.