The objective of this study was to evaluate the effect of rehydrating and ensiling dry ground corn (DGC) with varied concentrations of wet brewers grain (WBG) on fermentation profile and ruminal in vitro starch digestibility (ivSD; 7-h incubations on dried and 4-mm ground samples; Tilley and Terry, 1963). Samples of DGC and WBG were weighted separately and mixed following these treatments: 100% WBG (WBG); mix of DGC and WBG targeting for 60% (RC60), 65% (RC65) or 70% (RC70) of DM; and DGC rehydrated with distilled water targeting for 70% of DM (REH). Samples were ensiled in vacuum-sealed bags and allowed to ferment for 0, 1, 3, 7, 14 and 28 d. The experiment consisted of 30 treatments (5 mix of DGC and WGB × 6 ensiling times) and 120 mini-silos (4 silos per treatment). All samples were analyzed for fermentation profile and WSC. Except for WBG, samples from d 0 and 28 were analyzed for ivSD. Data were analyzed using Proc Glimmix of SAS with the Fixed effects of treatment, ensiling time and their interaction. Content of DM was greater (P < 0.05) for REH (70.0%), followed by RC70 (69.2%), RC65 (63.9%), RC60 (58.4%) and WBG (17.5%) on d 0, with a decrease (1–2 percentage units) observed for all treatments until d 28. Measurements of pH were (P < 0.05) greatest for REH (6.19) and lowest for WBG (4.68) on d 0, but all other treatments were lower than WBG on d 14 and 28 (3.83 vs. 4.14, on average). Except for WBG, all treatments had (P < 0.05) a gradual increase in lactate concentration from d 0 to 28. In contrast, butyrate gradually increased (P < 0.05) from d 0 (0.25%) to 28 (2.16% of DM) in WBG but not the other treatments. Fermentation patterns are related to WSC concentration which were greater (P < 0.05) for all treatments than WBG from d 0 (1.41% on average vs. 0.38% of DM, respectively) to d 28 (0.37% on average vs. 0.19% of DM, respectively). Greater ivSD was observed (P < 0.001) for all treatments on d 28 than d 0 (48.0% vs. 38.1% of starch, respectively) but magnitude of the difference was greater for REH and RC70 (14.5%-units on average). Rehydration and ensiling of DGC with WBG resulted in adequate fermentation and enhanced starch digestibility.