This paper investigates seismic behavior of a new beam to column connection with slit dampers. The connection prevents damages of beam, column, panel zone and welds. Plastic deformations occur in dampers. The slit dampers were made with I-shape profiles that had some slits in the profiles webs. One of specimens had just one slit damper which connected beam to column (SDC1) and I-shape profile without any slit was located at the bottom flange of the beam. Other specimen had two identical slit dampers which connected beam to column (SDC2). Specimens were tested under cyclic loading. The cyclic loading continued until 0.06 radian rotation. The results show that moment of specimen with two slit dampers increases until 0.04 story drift. Moment of specimen with just one damper decreases after 0.03 drift. The specimen SDC2 has higher seismic performance and more ductility than specimen SDC1. Also, theoretical and numerical studies has been done. The studies had good agreements with experimental results. According to experimental and numerical results, high rotational capacity of the connection is related to plastic deformations of slit dampers. The proposed connection shows high energy dissipation and ductility.Maximum bending moment of specimens SDC2 and SDC1 were 1.73 and 1.4 times plastic moment of beam section respectively. Also, the absorbed energy ratio of specimen SDC2 to specimen SDC1 is 1.51.