Shell-and-tube heat exchanger is a device commonly used to transfer heat. To enhance the heat transfer occurred and to support the tubes inside the shell, baffles are installed. Better heat transfer is obviously expected in a heat exchanger. A research is done to find out the effect of baffle used toward the effectiveness and pressure drop in heat exchanger. The result is that the effectiveness increases when the baffles are installed. Effectiveness increases as the spacing between the baffles is smaller until certain spacing, and then it decreases.