The temperature dependence of the DC resistivity of silver quantum dot self-assembled 2D Langmuir monolayers was obtained. The films exhibit a metallic-like resistance at high temperatures (above 200 K), and a thermally activated mechanism at intermediate temperatures (60-200 K) which strongly supports the model of a Mott-Hubbard band gap. The transition temperature from the metallic-like regime to the thermally activated regime was found to correlate with the activation barrier.