Recently, computational fluid dynamics (CFD) has been widely used for the prediction and analysis of cross-ventilation flows in buildings. In this study, detailed wind tunnel experiments were performed on the cross-ventilation flow of a generic single-zone building in order to compile a validation database for CFD methods. Both the velocity fields and the contaminant concentration fields were measured and investigated. First, the fundamental characteristics of the velocity and concentration fields in a cross-ventilated flow were investigated for the building in unsheltered conditions. Next, the distributions of turbulent scalar fluxes in a cross-ventilated flow, which have been rarely reported, were also measured, and the scalar transport mechanism was examined based on the results. Finally, the effect of the surrounding buildings on the cross-ventilation flow was investigated. This study shows that the turbulent velocity fluctuations and concentration fluctuations are clearly generated by different mechanisms. These results can be used to effectively and successfully validate CFD methods applied to the flow and concentration fields of cross-ventilation flows.