In Malaysia, Guinea grass (Megathrysus maximus) and Napier grass(Pennisetum purpureum) are considered as good palatable fodder for goats and have been used widely. The objective of this study is to evaluate the potential grasses for goats to have optimum growth performance and optimum feeding cost. Fourteen male Jamnapari goats with an average age of five months were used in this experiment. All animals were individually weighed anddivided equally (seven goats) into two treatment groups. Group 1 was fed with cut and carry Guinea grass while group 2 animals were fed cut and carry Napier grass, and both groups were given the same quality and quantity of PKC and molasses. There was no significant difference observed in the average final weight (AFW), average weight gain (AWG) and average daily gain (ADG) among the two dietary treatment group. However, dry matter intake (DMI) and feed conversion ratio (FCR) showed a significant difference. The group fed with Napier grass showed lower ADMI and FCR. From the viewpoint of economic evaluation, feeding Guinea grass and Napier grass as an animal feed is economincally viable for local farmers.