This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fixed-frequency pulse width modulator together with a data acquisition board and developed software. An UAV can be remotely controlled or flown autonomously by pre-programmed flight plans. The PWM controller was implemented through the guidance system on the UAV with control commands sent between the UAV helicopter and the ground control station via a wireless telemetry system. The PWM controller was tested and validated using LabVIEW 8.2. Several analyses were performed in a laboratory to test different control signals. The results obtained with the PWM controller on the UAV precision sprayer hold has promise as a technique to higher precision of spray applications that will improve efficiency of pesticide application, especially in crop production areas.