Many of the existing electricity markets are of the mixed type, which has pool auction and bilateral contracts between producers and distributors. In this case, the problem faced by a Generation Company (GenCo) is that of maximizing the revenues from participating in the market through the pool auction while honoring the bilateral contracts agreed, for which the revenue is fixed. The extension to mixed markets of a medium-term model, successfully employed for auction-only markets, is presented. It results in a non-convex expected revenue function to be maximized subject to constraints, for which the currently available direct global-optimization solvers prove not to be efficient enough. A heuristic procedure based on a sequence of solutions by a nonlinear solver is presented, and numerical results obtained with several realistic cases show satisfactory results. The test cases presented have dispatchable and non-dispatchable renewables and consider medium-term pumping together with conventional units by all GenCos participating in the mixed market. The advantages for GenCos of employingmedium-termresults as those produced by themodel presented, include, among others, the evaluation of the expected profitability of their bilateral contracts. L. Marí and N. Nabona were supported by project DPI2008-02153,A. Pagès was supported by projects DPI2002- 03330 and DPI2005-09117-C02-01 of Ministerio de Ciencia e Innovaci´on (Spain), project TRA2013-48180-C3-P of the Spanish Ministry of Economy and Competitiveness and the CYTED Program (CYTED2014-515RT0489).