Most recent seismic code put criteria for classified buildings to account the effect come shapernregularity. In the present research the buildings taken are regular in elevation and irregular inrnplan (L-shape). After checking elevation regularity and fundamental period of vibrationrnsatisfaction, the equivalent lateral force method of analysis used for analysis of earthquakernresistant buildings. Analysis was carried out reinforced concrete framed building wherernparametric study made to structure exhibiting different opening location-shape planer with variedrnprojections and varied story height based on capacity design principle. Seismic design makesrnuse of energy absorption and dissipation to reduce the design forces in order to achieve economyrnby properly accounting behavior factor based on code recommendation. Diaphragm discontinuityrnplays a great role on the response of building when the building exposed to different types andrndirection of loads. It affects the performance, top story displacement and base shear of building. rnIn this study, the evaluation of diaphragm discontinuity for elevation regular and plan irregular rnductile reinforced concrete structures using nonlinear analysis is investigated. The evaluationrnwas carried out by designing elevation regular and plan irregular structures for differentrnparametric condition (opening location, story height and projection lengths) with the provision ofrnthe Ethiopian seismic code and by checking their performance through non-linear analysis usingrnCSI ETABS. In this study parametric study has been conducted using same parameters includingrnseismic location, ground type, and ductility class, loading condition, behavior factor and materialrntype for all models. Moreover, the evaluation of diaphragm discontinuity using different modelsrnunder the same conditions along with performance comparison of structures designed for samernductility class (DCM) were carried out and the findings results are concluded as follows:- Forrnsame stories on different slab opened down positions the top story displacement decreases whenrnpushed to both x-and y-direction, especially at the slab opened at the projection part and therncomparison values clearly states that for the slab opened down at an angle, main part andrnprojection part, the base shears have decreased respectively when pushed to the x-direction andrny-direction. For same stories on different projection lengths, the top story displacement increasedrnby the same percent when pushed to x-direction and decreased when projection length increase rnto pushed to y-direction and the base shears decreased almost by same percent for all projections rnwhen pushed to x-direction and while the projection length increased, the base shears decreasedrnrespectively when pushed to y-direction. For different stories on same slab opened downrnpositions, the slab opened down in all stories led the top story displacement to be decreasedrnapproximately by the same percentage when pushed to the x direction and when the story levelrnincreased, the top story displacement decreased when pushed to y-direction and the base shearsrndecreased almost by same percent when pushed to the x-direction and the base shears decreasedrnwhen story height increased respectively, when pushed to the y-direction.