Engineers are constantly trying to improve the materials and practices of design and construction. One such improvement occurred in built-up structural members in the mid-1930'was castellated beam. The use of castellated beam for various structures is rapidly gaining appeal. This is due to the increased depth of the section without any additional weight, high strength-to-weight ratios and their lower maintenance and painting costs, increase in vertical bending stiffness, ease of service provision, and attractive appearance. However one consequence of the increased depth of the section is the development of various local effects. To fully utilize the engineering advantage of castellated beams, some provisions should be made in designing. With Finite element software ANSYS analysis was carried out on beam with increase in depth of opening, and results were validated with Experimental testing. Results obtained from testing and ANSYS are showing little variations. From ANSYS analysis and experimentation, it was proved that castellated beam up to profile depth 0.6D behave satisfactory for serviceability criteria.