DPX PE350, an experimental herbicide, has shown excellent potential for controlling a wide range of problem broadleaf weeds in cotton. PPI, PRE, and POST applications of DPX PE350 at 0.1 and 0.2 kg ai/ha were evaluated under weedfree conditions in 1991 and 1992 for effects on ‘Paymaster HS26’ cotton growth, yield, and fiber quality. In 1991, DPX PE350 applied PPI, PRE, or POST did not affect cotton population, height, yield, or fiber quality. In 1992, DPX PE350 applied PPI at 0.1 or 0.2 kg/ha or PRE at 0.2 kg/ha injured the cotton and reduced yield and micronaire value.