It has long been recognized that the evolution of hurricanes may be strongly affected by the air-sea flux transfer processes over ocean. High winds in a hurricane can generate large amounts of spray, which can modify the transfer of momentum, heat and moisture across the air-sea interface. However, whether or to what extent the sea spray can affect the hurricanes, especially the extratropical hurricanes, has remained elusive. In this study, the impact of sea spray on mesoscale numerical simulations of extratropical Atlantic hurricanes is investigated using a coupled atmosphere-sea-spray modeling system. Two case studies of extratropical hurricanes, Earl and Danielle from 1998, are analyzed. We found that: 1) sea spray can cause a significant latent heat flux increase of up to 20% of the interfacial fluxes in Earl, and up to 70% of the interfacial fluxes in Danielle; 2) taking into account the effects of sea spray, the intensity of a modeled extratropical hurricane can be increased by 20% in 10-m wind speed in Earl, and 30% in Danielle; 3) the maximum deepening of SLP and the maximum enhancement of surface winds due to sea spray occurs on the high-wind side near the hurricane center. Overall, sea spray has a notable impact on extratropical hurricane evolution.