The seismic behavior of the steel connection equipped with the lead extrusion damper (LED) is examined through the experimental and analytical studies. The LED implemented has spherical type bulge and does not consist any lubricant layer. The experimental study is performed in Structural and Earthquake Engineering Laboratory of Istanbul Technical University (STEELAB). In the experimental part, force-displacement relations of the connections with and without LED are achieved for the reversal displacement cycles. The measures of the dissipated energy, the equivalent damping ratio and the effective stiffness are obtained from the experimental study and compared for the connections. The total energy dissipated by the connection with the LED is approximately 175% greater than the total energy dissipated by the bare connection. In the analytical part of the study, nonlinear dynamic time history analyses are performed for the selected earthquakes and mass condition using the analytical models for the connections with and without LED. The maximum top displacement decreases approximately 50% for the connection equipped with the LED respect to the bare connection for the considered earthquakes. The maximum value of restoring force for the connection equipped with LED is approximately 25% greater than the bare connection for the accomplished analyses. Finally, the LED responses obtained in the nonlinear time history analyses are compared with the isolated LED test results.