In this experiment a sport drink was developed from coconut water and water melon juice. Six formulations were made designated SD1, SD2, SD3, SD4, SD5, and SD6 at the ratio of 100:0, 90:10, 80:20, 70:30, 60:40, 50:50 respectively and sensory evaluation carried out. Sample SD1 scored best for taste (1.58 ±0.50), SD2 was preferred for aroma (3.30±1.26), and sample SD6 had the highest for appearance and general acceptability. Four best formulations were taken from the sensory evaluation results, (SD1, SD2, SD5 and SD6) and subjected to various analyses including proximate composition, mineral, vitamin C, total sugars, total solids and microbial safety using standard methods. Results of the proximate analysis showed a decrease in moisture content (94.99±0.05 to 94.56±0.04) protein, (0.72±0.02 to 0.65.0.01), lipid(0.20+0.01 to 0.16±0.01) and increase in fibre content (1.2±0.02 to 1.24±0.02) ,ash (0.35±0.01 to 0.43±0.01), and carbohydrate (2.62±0.02 to 2.96±0.03). There was a gradual decrease in the mineral content; the highest being potassium (223.18±0.08 to 193.00±0.02). The vitamin C content and total sugars in the formulated sport drink increased from (119.70±0.02 to 449.07±0.04) and (3.82±0.03 to 6.89±0.04) respectively, while the total solids decreased from 9.85±0.03 to 8.92±0.02. From the result of this experiment, sample SD6 (50% each of coconut juice and watermelon juice) gave values as the most preferred formulation for a good sport drink. Keywords: Coconut juice, watermelon juice, sensory evaluation, formulation, sport drin