We report on the fabrication of GaInN-based solar cells using GaInN/GaInN superlattices as active layers and also as underlying layers beneath the active layers. We obtained pit-free surfaces, even with a high InN molar fraction, using the superlattices. As a result, the maximum external and internal quantum efficiencies reached 60%, and 88%, respectively. The open-circuit voltage of the soalr cells was 1.77 V, the short-circuit current density was 3.08 mA/cm2, and the fill factor was 70.3%. A conversion efficiency of 2.46% was achieved at room temperature under simulared 1.5 sun × AM1.5G illumination using a solar simulator. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.