This study aimed at determining the effects of pelleted corn stover (CS) on chewing activity and ruminal pH of lactating dairy cows. A total of 45 cows (30 primiparous, 15 multiparous; 118 ± 33 DIM and 604 ± 70 kg BW), were used in replicated 5 × 5 Latin squares with 28-d periods, using a 2 × 2 + 1 augmented factorial arrangement of treatments. Rumen pH was measured every 2 h for 24 h (n = 5, rumen cannulated cows) during d 21, behavior was visually recorded every 5 min for 24 h (n = 10, same cows for all periods) on d 27. Diets contained 10 or 15% (DM basis) corn stover-based pellets processed with soybean meal (CS-SBM) or distillers grains (CS-DG) as protein sources. Treatments were (1) Control (CON); (2) 10% CS-SBM; (3) 15% CS-SBM; (4) 10% CS-DG; and (5) 15% CS-DG. Data were analyzed with the MIXED procedure of SAS (fixed effects: protein source, inclusion level, source by inclusion interaction, square, and period within square; random effect: cow within square); pH data were analyzed as repeated measures. Overall, cows on CON diet had the greatest DMI (P < 0.01), 29.4 ± 1.32 kg/d, compared with 24.7, 23.6, 26.5 ± 1.32 kg/d for 10% CS-SBM, 15% CS-SBM, 10% CS-DG, and 15% CS-DG, respectively. Cows on CON spent the least amount of time per kg of DM consumed (8.0 ± 0.80 min/kg of DMI) compared with all other diets (9.7 and 11.8 min/kg DMI for 10 and 15% inclusion, respectively). Within pellet formulations, protein source did not affect eating time (P = 0.28), whereas cows consuming 15% CS-SBM or CS-DG spent more time eating compared with 10% inclusion (264 vs 238 ± 14 min/d; P = 0.02). Ruminating time was similar with either CS-SBM or CS-DG regardless of inclusion level (P ≥ 0.17), averaging 409 ± 17 min/d. Despite differences in DMI and chewing activities, mean rumen pH was similar for all diets (5.87 ± 0.08; P = 0.13). Feeding corn stover pelleted with SBM or DG affected eating behavior and increased eating time per kg DM, which resulted in reduced dry matter intake. Further refinement of pellet size, hardness, or inclusion level may be warranted to effectively incorporate pelleted corn stover in dairy rations.