The objective of this study was to determine the effects of small versus large pens throughout the grow-finish period on growth performance of the pig. This experiment consisted of two replications. One wean to finish site within a large Midwestern commercial production system was used for both replications. The site consisted of four rooms. Within each room, one side of the aisle was set-up with the small pen treatment (SP; n = 96 pens [34 pigs/pen; 0.69 m2/pig]), while the other side was set-up with the large pen treatment (LP; n = 12 pens [272 pigs/pen; 0.69 m2/pig]). Pens were mixed sexed and when the first market group of pigs reached the targeted market weight in both treatments the trial was terminated. Starting and ending weights and average daily gain on a pen basis was recorded and calculated for a total of 6,528 crossbred pigs. Performance was analyzed using the PROC MIXED procedure of SAS. Small penned pigs had a higher ADG (P = 0.004) and overall gain (P = 0.05) than large penned pigs. In conclusion, pigs raised in small pens throughout the grow-finish period had a higher average daily gain and overall gain than pigs housed in large pens throughout the grow-finish period.