Cervical root fracture is a major clinical problem in flared root canals treated with different post and core applications. This in vitro study evaluated the stress transfer of different post and core systems to the cervical part of the artificially created flared root canals, by using strain gauges. The post-core systems investigated were: (a) cast post-core system without resin reinforcement, (b) cast post-core system with resin reinforcement, (c) pre-fabricated post and resin core with resin reinforcement. The post-core systems which were cemented on simulated roots were subjected to a load applied at an angle of 45 degrees to the long axis of the simulated roots. The strain gauges which were cemented to the cervical part of simulated roots were connected to the data acquisition module to measure and record the changes in strain data. Specimens restored with resin reinforcement either with cast post-core or pre-fabricated post and resin core transferred the stress to the cervical part of the artificial roots at a rate lower than conventional cast post-core system (P = 0.001; ANOVA and Tukey's post hoc test). It was concluded that the resin reinforcement of root canals before post-core applications reduces the stresses at the cervical part of the root surfaces.