order to ensure the building stability, it was necessary to determine the adequate dimensions of structural elements; this project deals with the calculation and design of reinforced concrete structure. Several figures and tables have been used to illustrate the text and contribute to a better understanding of the subject matter. The proposed apartment building is 23.25 m x 18 m dimensions. It is three-storey building and it has bedrooms, living rooms, dining rooms and bathrooms. The height of each floor is 3.20 m. All the building members (slabs, columns, foundations and stair) are calculated by analytical method by using the basic knowledge in civil engineering. The height of the beam is 55 cm; its width is 20 cm whereas the width of flange is 90.7 cm for longitudinal beams. The maximum and minimum bar of reinforcement bar at top for all beams is Ø16 the same to the reinforcement at bottom. The critical panel of slab was designed, slab thickness is 15cm the maximum size of reinforcement bar is Ø12mm .The high loaded column was designed and the maximum reinforcement bar size is Ø25mm.Links of Ø8 mm at 300 mm center to center were provided to hold main reinforcement bars. Foundation were designed by considering the bearing capacity Pb= 320 KN/m2 and designed upper load from columns. Each designed foundation is 200*200*50 cm and the maximum reinforcement bar is Ø20 mm in foundation. In order to provide access from floor to next floor stair was designed .Going of stair is 300 mm, riser is 150 mm, the flight height is 160 cm and its pitch is 29.530, that stair is reinforced by Ø16 mm.