A bridge is a structure built to span physical obstacles such as a waterbody, valley or road to have accessibility for people and vehicles. The design and construction of road bridges require an extensive and thorough knowledge of the science and technology involved with adequate experience of bridge engineering. In India, till now Pre-stressed concrete road bridges are designed and constructed according to Indian road congress guidelines as per IRC: 18-2000 code in which working stress method is adopted. Recently, Indian road congress has introduced another code IRC- 112: 2011 for the design of pre-stress bridges using limit state method. The study of bridge design using the limit state method is discussed to enlighten the recently introduced IRC-112: 2011. The present study has been performed to know the difference in design using IRC-112:2011 and IRC-18:2000 and attempt is made to study undefined parameters of IRC: 112-2011 such as span to depth (L/D) ratio. The present study is based on the design of PSC Box girder by working stress method using IRC- 18-2000 and limit state method using IRC- 112: 2011 code specifications. It is observed that for Box girder, L/D ratios are 33 and 26 respectively for limit state method and working stress method. In Box girder, bridge quantity of concrete can be saved in limit state method. The present study may help in limit state method of Box Girder Bride design for defining L/D ratio.