Abstract :Hydrilla verticillata (L. f.) Royle is one that many aquatic plants found growing in the stagnant waters such as rice fields and marshes. The existence of these plants in large quantities can impede water flow rate so that the plant is often removed and thrown away. Hydrilla plants containing Nitrogen 1.37% and 14.47% Organic Carbon, so the potential to be used as a green manure that can be given to the plant in the form of fresh or in the form of compost. This study aims to determine the effect of Hydrilla verticillata (L. f.) Royle as green manure on the growth of cocoa seedlings (Theobroma cacao L). The research was conducted in the village of Bungadidi district Tanalili Luwu Utara which took place in July-September 2016. The research was conducted in the form of an experiment which is based on a randomized block design (RAK) with a treatment that is without giving hydrilla (control = P0), giving fresh hydrilla 200 g/polybag (P1), 400 g/polybag (P2), and 600 g /polybag (P3), giving hydrilla composted 200 g/polybag (P4), 400 g/polybag (P5), and 600 g/polybag (P6). The results showed that administration of hydrilla composted at a dose of 600 g/polybag resulted in the growth of cocoa seedlings to be better that the number of leaves more (9,6 leaves), the higher seed (30,3 cm), a larger trunk diameter (5,2 mm) and more root volume (6,6 ml).