A critical issue that is raising concern among the scientists and engineers during the last decade in the Netherlands is the occurrence of relatively small earthquakes in the North part of the Netherlands (Groningen, Drenthe and North Holland). These earthquakes that have a non-tectonic origin and are related to the gas-field depletion, have caused feelings of anxiety among the residents of the area. Thus, investigation of the seismic vulnerability of the structures in the affected area is crucial and the necessity of it is increasing when taking into account the dominating type of buildings: unreinforced masonry structures. The present Master Thesis Project is focusing on the seismic assessment of the Dutch “Rijtjeshuis”. A seismic analysis of a series of unreinforced masonry houses in Groningen is executed, which indicates the response of the structure to seismic actions and identifies the near collapse state for a range of seismic scenarios. The assessment of the performance of existing buildings is usually done by either fully dynamical procedures (nonlinear time history analyses) or static pushover methods. Structural response is defined in the present study by non-linear static pushover analyses, using finite element software DIANA (Version 9.6). The capacity spectrum method, using the inelastic demand spectra, is followed after considering variability both in the material properties (thus capacity curves) and the demand spectra, with ultimate purpose the derivation of the fragility curves for this typology of structures. The fragility curves are necessary to allow for a reliability based judgment of the structure. The distribution of the seismic resistance is built up from several parameters the most important of which are the ground motion variability, within building variability, and building to building variability. Masonry as a material is characterized by high rigidity, low tensile and shear strength, low ductility and low capacity of bearing reverse loading. These are the main reasons for the frequent collapse of masonry buildings during earthquakes often responsible for a considerable number of casualties. In the majority of real cases building properties are not well known due to the variability in building materials and building techniques. The masonry structure examined in the present study is supposed to be representative of a class of buildings with similar structural characteristics, mechanical parameters have been considered as random variables. The material variability can be regarded as the most important source of uncertainty in the determination of structural response, with all other sources either deriving directly from its effects or being insignificant in size compared to it. After the variability in the material properties is taken into account and the pushover analyses have been executed, the behavior of this typology of structures is known with the pushover and capacity curves. The reliability of the model used for the pushover analyses, is based on the verification of the finite element model with an existing one made by TNO in the framework of the project “NPR 9998 - Rekenvoorbeeld betonconstructie (TNO pushover analyses in DIANA)”. The first model that is developed in the Finite Element Program DIANA FX+ (version 9.6) is made of reinforced concrete as the one made by TNO. After the model is certified, the material properties of the concrete wall are going to be replaced with the mean material properties of masonry (Calcium-silicate brickwork, typical approximately 1960-1985). All the material properties of the structure (referring to masonry only) are assumed to be random variables, to which normal probability distributions are associated based on realistic ranges of variation. The sensitivity study is done based on the mean values and the coefficient of variation of a dominant random variable which is chosen to be the tensile strength of masonry. The pushover curve of each analysis will be extracted with ultimate goal the derivation of the family of pushover curves for the different material properties and further the capacity displacement for each case. Following, the demand from different earthquake scenarios are examined: after a probabilistic seismic hazard assessment, the necessary knowledge of the likely earthquake actions at a subject site have been determined. After using Jayaram’s method for the derivation of the acceleration response spectra and accelerations- displacement spectra, the demand of each earthquake can be computed. The inelastic displacement demand, that needs to be calculated because of the energy dissipation observed during the performance of the structures under seismic loads, is derived using Lin and Miranda’s method, which is an accurate and non-iterative procedure. Finally, since both the capacity of the structure and the inelastic demand of each earthquake is known, the comparison between these values will reveal information about the performance of the structure for the examined limit state. Since the variability in both the material properties and in the ground motions have been considered, the probability of collapse for each earthquake can be calculated. The repetition of this procedure for all possible earthquakes and structures results in the fragility curve. As a conclusion, the fragility curve that came out has the expected behavior and is comparable to ones found in literature for unreinforced masonry structures. The assumptions made in the present study are discussed further and recommendations for future studies are done.