A field trial was conducted during 1982–3 and 1983–4 on a loamy sand soil to study the effect of magnesium application to the soil and in foliar spray in relation to various levels of nitrogen on the growth and yield of wheat. Results indicate that wheat responde significantly to magnesium application only at the higher level of nitrogen. At the higher level of N (120 kg/ha), the response of wheat to magnesium application (10 kg/ha) to the soil and in foliar spray was 56 and 68 kg grain/kg Mg, respectively. However, the corresponding values at a low level of N (60 kg/ha) were only 14 and 15 kg grain/kg Mg. Magnesium at the higher level of N increased the chlorophyll content of leaves, leaf area index, interception of photosynthetically active radiation, number of ear-bearing tillers and number of grains per ear. The higher level of magnesium (20 kg/ha) did not result in extra beneficial effect compared with the lower level of Mg (10 kg/ha). Maximum interception of photosynthetically active radiation by the wheat canopy coincided with the attainment of maximum leaf area index and chlorophyll content of leaves at 90 days after sowing.