SUMMARYEnergy efficiency (EE) is becoming more and more important in future wireless communications because of limited battery power in mobile terminals. In this paper, we compare EE of the distributed MIMO (D‐MIMO) and co‐located MIMO (C‐MIMO) in uplink systems. Taking into account both circuit and transmit power, we derive an analytical expression for EE of D‐MIMO and C‐MIMO systems in a composite Rayleigh‐lognormal channel. What is more, an optimization algorithm is proposed to get the optimal EE values while satisfying given spectral efficiency requirement for both D‐MIMO and C‐MIMO systems. Simulation results show that D‐MIMO systems are more energy effective than C‐MIMO systems when considering the realistic systems, and the optimal EE can be obtained by the proposed algorithm while satisfying given spectral efficiency requirement. Copyright © 2012 John Wiley & Sons, Ltd.