Despite the high level of vulnerability of unreinforced masonry structures under applied loads and the importance of their reliability evaluation, there is no formal methodology to assess the reliability of historic masonry structures. To develop an appropriate methodology, estimations of probabilistic models of structural resistance and load effects are required to formulate a limit state function. The stochastic characteristics of materials play key roles in the determination of probabilistic models of structural resistance. Therefore, in current study, methodologies for estimating the statistical characteristics of historic masonry materials through non-destructive tests are described. Best fit probabilistic models for load effects are also presented. Target reliability index and different approaches for calculating suitable targets for historic structures are described as well. Evaluation of the reliability level of historical structures through the recommended procedure would lead to more realistic and accurate levels of reliability estimation without requiring degradation of the historic structure.