The objective of this study was to evaluate the effect of feeding corn silage with highly digestible starch (HD) on productivity of lactating cows. Twelve Holstein cows (BW: 563 ± 46 kg; mean ± SD in mid- lactation (days in milk: 121 ± 52 d) were assigned to one of experimental diets containing HD or a conventional corn silage (CONT) at 35% of diet DM in a switch-back design with 3 21-d periods. Concentrations of neutral detergent fiber (NDF), crude protein (CP), and starch were 37.3, 8.8, and 33.1% for the HD corn silage, and 41.6, 8.1, and 30.9% for the CONT corn silage on a DM basis, and 7-h in situ starch digestibility was greater for HD compared with CONT corn silage (73.8 vs. 64.5%; P < 0.05). Dietary contents of NDF, CP, and starch were 31.8, 14.7, and 26.8% for the HD diet, and 33.3, 14.5, and 26.0% for the CONT diet on a DM basis. Treatment did not affect DMI (23.3 vs. 22.0 kg/d; HD vs. CONT, respectively), milk yield (34.0 vs. 32.6 kg/d), and concentrations of milk fat (4.00 vs. 4.04%), protein (3.34 vs. 3.30%), and lactose (4.53 vs. 4.55%). However, cows fed the HD corn silage decreased milk urea N (10.2 vs. 12.3 mg/dL; P < 0.05), tended to increase milk protein yield (1.13 vs. 1.06 kg/d; P < 0.10), and increased BW change (0.59 vs. −0.07 kg/d; P < 0.05) compared with those fed the CONT corn silage. Consistent with these results, cows fed the HD corn silage had lower (P < 0.05) concentrations of serum free fatty acids (78.3 vs. 94.2 µEq/L) and serum urea nitrogen (12.6 vs. 16.1 mg/dL). These results suggest that feeding HD corn silage can improve the efficiency of N utilization and energy balance of lactating dairy cows possibly by increasing starch fermentation in the rumen.