For estimation of seismic forces on buildings IS: 1893-2002 specified response spectra are used. Code specified zone factor and response spectra are applicable for the general soil conditions. But the peak ground acceleration and seismic effects on buildings depend on sub soil condition, as evident from damages occurred to buildings of Ahmedabad during Bhuj Earthquake. In the present paper response of soil to seismic event is evaluated in terms of site specific response spectra and acceleration time history at ground surface using software ProSHAKE. The site specific response spectrum obtained at various sites of Ahmedabad are compared with the standard response spectrum given in IS 1893:2002 for medium soil condition. The dynamic response spectrum and time history analysis of 3-D shear wall framed buildings, with different shear wall positions, is carried out using ETABS software. Comparisons of analysis results obtained in terms of time period, base shear and design forces in ground floor shear wall considering site specific response spectrum, acceleration time history and IS 1893:2002 standard response spectrum are carried out.