The major goal of the cucurbit breeding program of the World Vegetable Center (WorldVeg) is to catalyze cucurbit breeding research in partnership with the private seed industry, international research institutes and National Agricultural Research and Extension systems (NARES) and facilitate discovery, piloting, and scaling of new unique products that benefit all value chain actors such as farmers, distributors, retailers, and consumers. We focus on three cucurbit species: bitter gourd (Momordica charantia), tropical pumpkin (Cucurbita moschata), and loofah (Luffa cylindrica and L. acutangula). WorldVeg's bitter gourd breeding research has resulted in the development of lines resistant to powdery mildew (Podosphaera xanthii) and Tomato leaf curl New Delhi virus (ToLCNDV) and lines possessing fruit colors and shapes suitable for specific market segments, earliness, high yields and the gynoecious trait. We detected the narrow genetic base of commercial bitter gourd cultivars by simple sequence repeat analysis and demonstrated the diversity of our landrace NDASH derived breeding lines for developing unique F1 bitter gourd hybrids. Bitter gourd populations for further selection through inbreeding for enhanced yield, superior fruit quality and disease resistance have been created at WorldVeg for various commercial segments by crossing genetically unrelated bitter gourd cultivars and genebank accessions. Four cycles of recurrent selection and two inbreeding cycles have been completed. Tropical pumpkin breeding at WorldVeg has led to the development of open-pollinated lines rich in beta-carotene with good eating quality and resistance to various potyviruses and begomoviruses. Breeding for resistance to begomoviruses and improved fruit quality and yield are the objectives of CenterRSQUOs loofah breeding program.