Feeding and oviposition preferences of the boll weevil, Anthonomus grandis grandis Boheman, for four different cotton square size classes in field conditions of the Lower Rio Grande Valley of Texas were studied during 2002 and 2003. Percentages of large (5.5–8-mm-diameter) squares used for oviposition and feeding were greater than pinhead or match-head squares. The preference for large squares as food and associated accelerated fecundity explain the substantial boll weevil population buildups that occur after large squares form. Medium-sized (3–5.5-mm-diameter) squares also were used but less than large squares. Feeding and oviposition on pinhead (1–2-mm-diameter) and match-head (2–3-mm-diameter) squares were negligible. Although planting date did not affect oviposition or feeding preferences for squares larger than pinhead and match-head sizes, the least amount of either damage to large squares was found in the earliest plantings during both years. This study indicates that pinhead and match-head squares, regardless of planting date, do not require pesticide applications to protect against boll weevil feeding and oviposition.