“Castellated beam” is a name commonly used for type of expanded beam. Castellated beams combine beauty, versatility, economy in steel design. These are fabricated from standard rolled section and are engineered to save time of construction, enabling saving in steel and reducing building costs. These are mainly designed to reduce weight and at the same time increase the efficiency in structural performance. The principal advantage of castellation is the increase in vertical bending stiffness castellated beams have proved to be efficient for moderately loaded longer spans where the Design is controlled by moment capacity or deflection. In this paper a steel beam is selected and Finite Element Analysis is done for constant loading and support condition by using ANSYS software. The deflection pattern at the center of castellated beam is studied for different parametric conditions by changing depth of hexagon to the depth of web ratio and also by changing the position of hexagon along the length of the beam. A comparison is done for various conditions.