This paper presents, an analytical study carried out on High Strength Concrete (HSC) building frames using a nonlinear dynamic analysis computer program (IDARC-M). The program was originally developed for the analysis of normal R.C. frames and it was modified to predict the response of HSC frame structures. Unlike most of conventional investigations into HSC beam-column connections, this work considers such connections as integral part of the studied ten-story HSC frame. The inelastic behavior of an interior beam-column connection in the first floor was studied. It was found that the use of HSC improves column capacity, enlarges rigidity of beam-column joints, reduces the effect of lateral reinforcement distribution in beams and columns, and decreases the fundamental natural period of the frame. The type of column support at foundation level has a great effect on the drift of the studied building frame.