This research aimed to determine the optimum pot size and fertilizer dosage for melon (Cucumis melo L) cultivation based on productivity. The experiment used a Completely Randomized Design (CRD) arranged factorially with 2 factors and two replicates. The first factor was the dose of compost fertilizer (D) which consists of 1500 g (D1), 1500 g+10 g NPK (D2), 2000 g (D3), and 2000 g+10 g NPK (D4), and the second factor was the pot size or volume of growth media (N) consisting of 5 liters (N1), 10 liters (N2), and 20 liters (N3). The results showed that fertilizer dosage had no effect on all parameters, while pot size had an effect on fresh fruit weight, plant height, fruit circumference, stem diameter and water productivity, but had no effect on sweetness level, number of leaves and root weight. If seen from fruit weight and water productivity, the N2 treatment factor is the best treatment factor. Therefore; the D1N2 treatment combination could be chosen as the optimum treatment because it produced fruit weights of 1434.58-1532.36 g and an average water productivity of 39.07kg/m3. Keywords: Compost Dose, Melon Cultivation, Pot Size, Water Productivity.