Field experiment was conducted at Kogi State University Research and Students’ Demonstration Farm, Anyigba in the Guinea Savanna agro-ecological region in North Central Nigeria during the raining season of 2019 to determine effect of phosphorus (P) on the growth characteristics and individual yield of water melon. The experiment consisted of a variety of water melon (Kaolack) treated to five (5) levels of P: 0, 25, 50, 75, and 100 kg P2O5/ha on the growth characteristics and yield of water melon, laid out in Randomized Complete Block Design (RCBD), with five replications. Data were obtained for both growth characteristics and yield parameters, such as number of leaves, vine length, number of branches, days to first flowering, days to 50% flowering, number of fruits harvested, weight of harvested fruits, and fruit yield / ha. The results showed no significant (P≥0.05) effect of cow dung-based P on number of leaves, vine length, number of stem branches at 9WAS, days to 50% flowering and number of harvested fruit. However average fruit weight and fruit yield per hectare responded significantly to P treatment with 50 kg P2O5/ha giving the highest response in relation to water melon yield thus recommended for the experimental area.