The African oil palm (Elaeis guineensis Jacq.) is the highest yielding oil crop and the major source of vegetable oil worldwide. As a perennial crop with a typical life cycle of 25 years, establishment costs are high but potential yields of up to 8 tons of oil per hectare can be achieved under favourable environments and with best agricultural practices making it one of the most pro¿table land-uses in the humid tropics. Due to the radial symmetry of the foliage and their fasciculate root system, oil palms are typically planted in an equilateral triangle design. Spacing between palms de-termines planting density, a major contributor to oil yield. With a spacing that is too large, resources such as incident radiation are underutilised; on the other hand, too low a spacing excessive competition between palms will have a depressive effect on yield. As leaf mass and span increase over the ¿rst 12 years after planting, optimum density decreases with age. As a result of all these issues, the optimum planting density is the one that will achieve the highest cumulative yield over the 25 years cropping cycle. This study presents the results from a 12 year old spacing trial in Nigeria. The highest cumulative yields per palm are recorded for the lowest density but the highest cu-mulative yield per hectare are still observed on the higher densities. However, the gap between both is shrinking with time as the competition for incident radiation in-creasingly affects the higher densities. While optimum density for cumulative yield at 12 years after planting is still 190 palms ha-1, extrapolation and simulation indicate an optimum between 143 and 160 palms ha-1over the entire cycle, corresponding to a spacing of 8.5 to 9 m.