In Experiment 1, the diets were offered for 42 d to 96 individually penned gilts (29.0 ± 0.2 kg) to give 8 pigs per diet. An interaction between diet type and xylanase was observed for ADG (P < 0.05) such that pigs fed wheat diets with xylanases A and C and corn diets with xylanases A and D had greater (P = 0.044) ADG than pigs fed xylanase-free diets or wheat diets with xylanase D or corn diets with xylanases B and C. A main effect of xylanase was observed for G:F in which case xylanase A improved G:F by 10% (P = 0.010) compared to the control