Abstract: The equations to calculate the short-term stiffness of flexural hybrid reinforced concrete (hybrid-RC) members with fiber-reinforced polymer (FRP) and steel bars were derived upon the stiffness analysis method. Experimental data of 96 hybrid-RC members were collected to establish a database. The coefficient considering the variation of tensile strain in reinforcements was determined by fitting the data from the database. The short-term stiffness calculation model proposed, as well as the calculation models in the Chinese industry standard of JTG 3362-2018 and American codes of ACI 318-19 and ACI 440.11-22, was evaluated by the database. The results demonstrate that the short-term stiffness model proposed could provide accurate deflection predictions, with an average ratio of calculated to experimental deflections of 1.01. The model specified in the Chinese industry standard significantly overestimated the stiffness of hybrid-RC members, and this model was modified by incorporating a cracking moment reduction factor of 0.65. In addition, a comparative analysis for the four models was conducted to evaluate deflection calculations within the load range from zero to yielding load.