Spring wheat seeding rates of 22, 45, 67, and 101 kg/ha were compared in a field experiment on a medium-textured soil at Swift Current, Saskatchewan, over the period 1960–1968. Data collected during eight years indicated that when weeds, insects and diseases were chemically controlled, low seeding rates produced significantly more grain than higher seeding rates, with greatest increases occurring during years of severe moisture stress. Low seeding rates produced longer heads, heavier kernels, and in some cases taller plants. Plant population differences resulting from the variation in seeding rate were largely eliminated by plant survival and tillering. The number of mature kernels per unit area did not differ significantly for all treatments.Seeding rates had an effect on the rate at which moisture was used by the crop. Soil moisture supplies were quickly exhausted on plots seeded at rates of 67 and 101 kg/ha, whereas moisture was available to the crop seeded at lower rates over a longer period. The crop seeded at 22 kg/ha matured 3 to 5 days later than that seeded at 101 kg/ha.