This research evaluated the influence of varying dietary corn particle size (CPS) on body weight, feed consumption, and feed conversion of broilers grown to 21 days of age. Previous research has demonstrated that CPS can influence feed costs, nutrient digestibility, and potential profitability. Broiler starter diets with CPS of either 832, 1432, or 2036 μm were fed to 288 male Cobb 700 broilers over a 21-d battery cage grow out (6 replicate cages per treatment; 96 birds per treatment). Bird weights and feed consumption data were collected at 7 d intervals. At study termination, 6 birds per cage were euthanized for organ data collection (crop, proventriculus, gizzard, and ceca). Data were analyzed as a completely randomized design, with battery cage representing the experimental unit, using the GLM procedure of SAS. Means were separated using Tukey’s HSD and statistical significance considered at P≤0.05. There were significant treatment effects for average body weight at d 7 (P=0.050), with birds on the 832 μm CPS diet weighing more (180.3 g) than birds on 1432 and 2026 μm diets (176.5 and 169.0 g, respectively). There were, however, no CPS effects on BW at d 14 and 21 (P>0.05). Overall, there were no significant treatment effects for feed consumption d 0 to 7 (P=0.429), 0 to 14 (P=0.511), or 0 to 21 (P=0.939); and feed conversion d 0 to 7 (P=0.832), 0 to 14 (P=0.252), or 0 to 21 (P=0.189). Additionally, there were no observed treatment differences for mortality anytime during the 21 d grow out (P>0.05). Corn particle size did not influence relative (g/kg BW) crop, gizzard, or ceca weights. However, birds on 832 μm CPS had 14 and 13% larger (P<0.05) relative proventriculus weights respective to the 1432 and 2036 μm treatments.