The MESH-CLASSIC model is a coupling of the Mod´elisation Environmentale Communautaire Surface and Hydrology system (MESH) hydrologic model, and the Canadian Land Surface Scheme Including Biogeochemical Cycles (CLASSIC) land surface model. It was developed for the purpose of investigating the impact of hydrologic processes on biogeochemistry at the site and catchment scale and builds upon previous work to couple the Canadian Terrestrial Ecosystem Models (CTEM) to MESH, with the ultimate goal of succeeding the MESH (with CLASS physics) hydrologic model for use within ECCC and by the Canadian hydrological modelling community. To evaluate model performance, MESH-CLASSIC has been run at four flux tower sites in Southern Ontario, including three different-age managed conifer forest sites, one deciduous forest site and an agricultural site in the Big Creek catchment area. MESH-CLASSIC’s model performance will be compared with the observed flux data at site level and the simulations from the uncoupled MESH model for carbon, water and energy at catchment scale.