The rapid growth of wireless services has imposed huge pressure on the fixed radio spectrum. The deficit in the limited radio frequency spectrum resources can be alleviated by adopting cognitive radio technology. This new concept aims to change the traditional static spectrum allocation into a dynamic one by exploiting unused frequencies. Researchers in cognitive radio context have been more interested in spectrum sensing and sharing concepts than spectrum handoff. However, node mobility still arises as a major issue. To this extend, we develop a new approach for spectrum sharing and handoff taking into account nodes mobility. Our proposal uses multi-agent systems negotiation that enables mobile cognitive radio terminals to switch to the best available spectrum band giving their applications requirements. We deploy agents on both primary and secondary users to exchange information and negotiate in order to have a better use of the spectrum, considering devices capabilities and requirements. Simulations results show that our approach achieves up to 97% of the whole spectrum utilization and reduces the number of spectrum handoffs.