Abstract: `Egusi` melon is an important seed vegetable crop in Nigeria. There is scanty information on its cultural practice requirements for optimum seed yield. Field studies were conducted during the early and late seasons of 2002 on an affisol to determine the appropriate source and time for N fertilizer application and to identify the appropriate index leaf for N diagnosis. One `egusi` melon cultivar, Black � edged seed `bara` and two N sources [urea and Calcium Ammonium Nitrate (CAN)] at 0 and 60kg.N ha^-1 were investigated. The N fertilizers were applied at five different growth stages as split or single dose. The 2�5 factorial treatment combinations were arranged in a randomized complete block design and replicated thrice. `Egusi` melon growth parameters, seed yield and nutrient contents in different leaf positions were assessed. Data obtained were analyzed using ANOVA. Split application of N fertilizer significantly (p 0.05) improved `egusi` melon growth and seed yield compared to single dose. Split application of N as half dose at planting and remaining half at vine initiation gave highest melon seed yield. Urea as a source of N fertilizer was found to show an outstanding performance in both seasons, irrespective of the time of N application compare to CAN. The 5th and 6th leaf positions recorded the highest nutrients concentration. Based on the high nutrient contents of the 5th and 6th leaves, they could serve as an indicator of yield and therefore, be used as index leaf.