The effect of varying plant population and spatial arrangement on the production of buttercup squash (Cucurbita maximaDuchesne) was examined. Plant populations were set between 0.2 and 6.2 plants/m2in rows 1.5 and 3.0 m apart and at equidistant spacing within and between rows. The spatial arrangement of the plants in the three planting patterns had little effect on the production and fruit size of the squash compared with the effects of plant population. It was concluded that squash exhibited high elasticity in relation to the spatial arrangement at planting with row width and rectangularity of planting having much less influence on production parameters than plant population. Increases in plant population gave a progressive decline in the size of the individual squash plants and the number and weight of the fruit. Fruit number/m2of fruit heavier than 0.8 kg increased from 1 to 2/m2as populations increased from 0.23 to 2.5 plants/m2but they then declined. Average fruit weight declined from 1.9 kg at low plant populations of 0.2–0.4 plants/m2to 1.2 kg at populations 2.2–2.5 plants/m2, and below 1 kg at a plant population of 4 plants/m2. Significant numbers of squash above 2 kg were only achieved at low populations and only obtained with a considerable loss of potential yield. At low plant populations 3.0-m row plantings gave a greater percentage of larger fruit. As the plant populations increased the fruit size became more uniform. Total fruit yield increased to the highest calculated yield of 29.5 t/ha at a plant population of 3 plants/m2and then gradually declined. Above 2.2 plants/m2, the crop yield was predominantly in the fruit size range of 0.9–1.1 kg/fruit and sowing plant populations above 2.2 plants/m2would only be beneficial if this size of fruit was marketable. It is recommended buttercup squash be planted at populations of 1.8–2.2 plants/m2.