Sixteen field experiments were conducted across Oklahoma to evaluate the effects of MON 37500 time of application on cheat control, and winter wheat injury and yield. Winter wheat injury from MON 37500 applied preemergence (PRE) was slight and was influenced by cumulative precipitation for 10 d after application. Winter wheat injury was more frequent with early vs. late postemergence (POST) applications and was influenced by wheat growth stage and mean, high, and low air temperatures before and after application. Cheat control averaged 75% (n = 16 treatments with four to six replicates) when applied PRE and 88% (n = 126 treatments with four to six replicates) when applied POST. Cheat control from MON 37500 applied POST declined with increasing cheat growth stage at application and with decreasing mean diurnal low temperatures 0 to 14 d and 0 to 21 d before application. MON 37500 applied PRE increased yields 52 and 66% compared with the untreated control in Year 1 and Year 2, averaged over eight experiments each year. MON 37500 applied POST increased wheat yields 68 to 69% compared with the untreated check in Year 1 and Year 2, when averaged over all applications in eight experiments each year. Wheat yields were greater from fall POST applications than from late-winter applications.