This paper describes an experimental programme in which two one-storey single-bay specimens were tested under cyclic lateral loading. The first specimen was designed according to the normal practice for framed masonry structures, whereas new reinforcing details were provided in the second specimen, with the objective of enhancing the structural response. Special precautions were taken for the application of the lateral forces, considering that experimental and analytical results indicated that the loading system could markedly affect the structural response. Consequently, an adequate procedure should be adopted for laboratory tests in order to obtain realistic data. The most important conclusion of the experimental programme was that the response of reinforced concrete frames with masonry infills can be significantly improved by a rational design aimed at reducing the distortion of the masonry panels while the plastic deformations are concentrated in selected regions of the structure.