The objective of this study was to compare rehydrated corn grain silages using water or whey and inoculated (Lactobacillus plantarum and Propionibacterium acidipropionici) or not. We also verified whether rehydration with whey associated with the bacterial inoculant improves material conservation. The treatments were as follows: silages rehydrated with water without inoculant (SWa); silages rehydrated with water and inoculated (SWaI); silages rehydrated with whey without inoculant (SWe); silages rehydrated with whey and inoculated (SWeI). A completely randomized design was used, with three replications, treatments in a 2 × 2 factorial scheme (RE: rehydration with water or whey, and IN: inoculation or addition of water without chlorine), during the following storage periods (T): 0, 4, 8, 16, 32, and 64 days. There was an RE x IN x T interaction (P < 0.001) for dry matter (DM), with lower values over time for SWe and higher values in SWeI. An interaction between RE x IN (P < 0.001) and IN x T (P < 0.001) was observed for pH, with higher values for SWe at 64 days of storage and a reduction from the first days of ensiling for SWaI and SWeI. The microbiological variables showed an RE x IN x T interaction (P < 0.001), with the highest counts of lactic acid bacteria for SWaI and SWeI up to 8 days of storage and subsequent higher counts in SWa and SWe. Higher counts were obtained in SWe. For the variables of fermentative losses, there was an RE x IN x T interaction (P < 0.001), with SWeI showing lower losses. The inoculation associated with whey for rehydration of corn grain improved the fermentation profile of the silage, with lower pH values and reduced losses.