Twelve lines of watermelon (Citrullus lanatus Thunb.) with resistance to Watermelon chlorotic stunt virus (WCSV) were morphologically characterized and association among pairs of characteristics was estimated. These watermelon lines were developed at the National Institute for Promotion of Horticultural Exports-University of Gezira-Sudan. Wide differences exist among these lines with respect to vegetative, inflorescence, fruit and seed characteristics. High variation coefficients were obtained for seed weight (51%), number of secondary branches (45.6%), fruit weight (41.7%), rind thickness (41.2%) and seeds/kg (40.3%). Plant canopy was positively associated with male flower (0.51) and ovary length (0.56). While female flower size and ovary length was positively associated with fruit weight (0.57; 0.63), the latter was also positively associated with total soluble solids (TSS) (0.51), seed size (0.73) and seed weight (0.63). Also, male flower size was positively associated with ovary length (0.6), fruit weight (0.64), TSS (0.54) and seed size (0.52). However, flower earliness (50%) was negatively associated with female flower size (-0.61) fruit weight (- 0.56) and number of seeds/kg (-0.53). These lines are being used for the development of superior hybrid lines and genetic mapping.