Abstract: Cleopatra mandarin (Citrus reticulata reshni) citrus rootstock seedlings were intercropped with cucumber (Cucumis sativus Cv. Poinstett) in the nursery at different plant densities of 10,000 (1 x 1 m), 4,444 (1.5 x 1.5 m), 2500 (2 x 2 m) and 1600 (2.5 x 2.5 m) ha-1 during the late planting season of 1998 and 1999. The studies were aimed at determining the optimum cucumber density compatible with Cleopatra mandarin citrus rootstock seedlings, which should also serve as income generation to the nursery citrus farmers with minimal hindrance to the growth of the citrus seedlings. The cucumber population above 2,500 plants ha-1 significantly affected the growth of Cleopatra mandarin rootstock growth seedlings. The percentage increases in plant height, number of leaves and stem diameter in intercrop of cucumber population below 2500 plant ha-1 were higher than rootstock seedlings intercropped with cucumber population above 2500 ha-1. However cucumber growth was not affected by intercropping or the population intercropped with citrus. Cucumber intercrop of 10,000 ha-1 gave the highest yield of cucumber fruit, while the highest profit margin of 80.3% was recorded by cucumber intercrop of 4,444 ha-1. Cucumber intercrop of 1600 ha-1 had the lowest profit margin of 66.2%. Cucumber population of 2500 ha-1, which recorded 78.7% profit margin, is suggested as optimum for minimal hindrances to citrus seedlings growth and modest cucumber yield.