Montane meadows are highly productive ecosystems that contain high densities of soil carbon (C) and nitrogen (N). However, anthropogenic disturbances that lead to channel incision and disconnected floodplain hydrology have altered the C balance of many meadows, converting them from net C sinks to net sources of C to the atmosphere. Restoration efforts designed to reconnect floodplain hydrology may slow rates of soil C loss from degraded meadows and restore conditions for C sequestration and N immobilization, yet questions remain about the long-term impact of such efforts. Here, we used a 22-year meadow restoration chronosequence to measure the decadal impact of hydrologic restoration on above- and belowground C and N stocks and concentrations. Increases in herbaceous vegetation biomass preceded changes in soil C stocks, with the largest gains occurring belowground. Root biomass (0-15 cm) increased at a rate of 270.3 g m^-2 y^-1 and soil C stocks (0-15 cm) increased by 232.9 g C m^-2 y^-1 across the chronosequence. Increases in soil C concentration (2.99 g C kg^-1 y^-1) were tightly coupled with increases in soil N concentration (0.21 g N kg^-1 y^-1) and soil C:N did not vary with time since restoration. Fourier Transformed Infrared Spectroscopy results show that the fraction of labile aliphatic C-H and carboxylate C-O (COO) compounds in the soil increased with age of restoration and were positively correlated with soil C and N concentration. Our results demonstrate that restoration of floodplain hydrology in montane meadows has significant impacts on belowground C and N stocks, soil C and N concentration, and soil C chemistry within the first two decades following restoration.