The objective of this work is to contribute to cover the information gap with respect to the estimation of the municipal GDP by presenting a calculation methodology based on the estimation of the differential sectoral productivity of the city with respect to its Autonomous Community. Sectoral wage differentials between cities and Autonomous Communities estimated from the Continuous Sample of Labor Lives for the period 2010-2016 are used. The results seem to indicate that relevant aspects of the economy of cities are being collected, such as, among others, potential economies of agglomeration.