Field experiments conducted in Marianna, Trenton, and Archer, FL in 1990 and 1991 investigated the effect of time of application of nicosulfuron and nicosulfuron mixtures on ‘Sunrunner’ peanut. Nicosulfuron was applied alone at 36 g ai/ha and in mixture with acifluorfen, bentazon, chlorimuron, chlorothalonil, fluazifop-P, imazethapyr, lactofen, or pyridate at 5, 7, or 9 weeks after planting (WAP). Applying nicosulfuron with chlorimuron, pyridate, or imazethapyr increased visible peanut injury and reduced yields more than nicosulfuron alone. Conversely, nicosulfuron applied with acifluorfen or lactofen was less injurious than nicosulfuron applied alone. Bentazon, chlorothalonil, and fluazifop-P generally did not influence phytotoxicity from nicosulfuron. Peanut tolerance to nicosulfuron increased with age.