Fuel cells are one of the promising renewable energy resources due to their attractive features such as high efficiency, high reliability, modularity and the ability of providing heat and power. Connecting the fuel cells to the grid is a challenging process due to the slow transient response of the fuel cell, the change in output voltage value of the fuel cell with the change in load and the output voltage level of the fuel cell is low compared to that of the grid. A simple yet reliable structure of a fuel cell-based distributed generation system that is ready for integration with the existing power grid is presented in this paper. The proposed system consists of three fuel cell modules connected in parallel through three DC/DC converter circuits. The connection to the grid is accomplished through a DC/AC inverter and a power transformer. The active power and reactive power injection to the grid is adjusted by controlling the inverter operation. The main goal of presenting this system in this paper is to study and investigate the fuel cell performance in grid-connected operation under steady-state and transient condition. The proposed system is simulated using MATLAB-SIMULINK platform.