Purpose: The purpose of the presented study is to develop fragility curves for the wide-beam infill-joist block reinforced concrete structures. Theory and Methods: Nonlinear time history analyses are performed for the set of selected ground motions. The performance levels are identified through pushover analysis and fragility curves are produced for ground motion parameters. Results: Fragility curves obtained for the wide-beam RC frames presents a different characteristic than the curves obtained for the conventional frames. Conclusion: Results show that wide-beam RC frame buildings are seismically more vulnerable than the conventional deep beam RC frame buildings based on structural models with similar properties. The possible reason seems to be low lateral stiffness of wide-beam frames that causes large lateral drift demands and therefore severe damage at the wide-beam column connections.