This thesis is concerned with the effect of change in yield strength of reinforcement steelrnon the safety and strength of reinforced concrete beams and columns. Of different possiblerntypes of beams and columns, simply supported beams and short columns are considered inrnthis study.rnParameters like moment capacity, total steel area, neutral axis depth, ultimate loadrncurvature and stiffness of the beam and total steel area of the column are taken. Therngeneral trend observed in behavior due to the change in yield strength is assessed and havernbeen presented graphically.rnBoth the beam and the column are first designed using limit state design methodrnemploying the appropriate partial safety factors for loads and materials. Next they arerndesigned for service loading keeping other conditions the same as before using a factor ofrnsafety equal to one for concrete and steel. Then the difference in capacity between therndesign results is evaluated. As this difference is the reserve capacity we have as a safetyrnmargin, the effect of the change in yield strength is evaluated with respect to this capacityrnand presented graphically to show that by how much safety margins are compromised.rnFinally, conclusions and recommendations have been made based on the findingsrnKey words: over–reinforced concrete beams, under–reinforced concrete beams, yieldrnstrength of steel, capacity parameter.