In this paper, results of experimental and analytical studies on a new type of infilled frames, having high ductility are presented. The studied infilled frames, regarded Engineered, had frictional sliding fuses at their mid-heights. The fuse could be regulated for a desired sliding strength in longitudinal direction, but was restrained transversally. In the first part of the paper, experimental results of two engineered infill specimens, with different sliding strengths of their fuses, are presented. Cyclic loads were applied to the specimens. It is shown that such infills have more stable hysteresis loops as well as higher ductilities, in comparison with regular infill panels. After having the experience of failure by in-plane loads, the specimens were tested again; one of them was repaired by grout and reloaded by the same loading protocol. The other one was loaded transversally to evaluate the out-of-plane strength of the engineered infills after being failed by in-plane loads. Results show that such infills have high transversal strengths and they can be efficiently repaired by grout. In the second part, behavior of the engineered infilled frames (EIFs) in real earthquakes are studied and compared with ones of bare frame and regular reinforced concrete infilled frame. For this, some nonlinear time-history analyses of a three bay frame with 1, 3, 5 and 7 stories were conducted by IDARC for five earthquake records. It is shown that the engineered infilled frames are efficient to improve seismic behavior of the considered buildings.