The no-tillage system is considered an important tool for sustainable production. In this system, the burndown of brachiaria is usually performed with the application of systemic herbicides, such as glyphosate. As a result of environmental conditions (temperature, relative humidity and winds), the timing of spraying can directly interfere in the control efficiency. Therefore, the objective was to study different times of application of glyphosate in the control efficiency of Urochloa brizantha cv. Marandu. The glyphosate was applied in the morning, afternoon and evening, at doses of 0; 360; 720; 1080; 1440 and 2160 g a.e. ha-1. To analyse the efficiency of U. brizantha burndown, the phytotoxicity was evaluated at 21 days after application. At 42 after application a mowing was done and 90 days after mowing, the dry matter accumulation and the Leaf Area Index of regrowth were determined. The best control results of Urochloa brizantha cv. Marandu were obtained in the applications of glyphosate during the morning and afternoon. Evening applications of glyphosate should be avoided.