This thesis is concerned with effect of vertical component earthquake groundrnacceleration on the response of reinforced building structure. Basically thernstudy focuses to assess the effect of vertical component earthquake groundrnacceleration within zone 4 and near fault area of Ethiopia. To achieve thesernobjectives varying source distance and soil profile were used to analyzernselected building in linear response spectrum analyses. The results like axialrnforce, shear force and bending moment were used to know effect of verticalrncomponent of earthquake ground acceleration. From these, ignoring verticalrncomponent of earthquake ground acceleration at near fault causesrnconsiderable amount of internal response. The effect of vertical earthquakernground acceleration decreased as epicentral distance increased and becomernalmost similar with effect of lateral earthquake ground acceleration at farrndistance. To sum up this, source distance, soil profile and magnitude ofrnearthquake were a main factor to determine peak response of verticalrnearthquake component at near source.rnGenerally, including vertical component earthquake ground acceleration inrndesign of reinforced concrete building structure within zone 4 of Ethiopia is notrnthat much important compared to the lateral components. But verticalrncomponent earthquake ground acceleration should be considered if thernproposed building structure is sited around near faults.rnKEYWORDS: Vertical earthquake component, internal response, near fault,rnnear source factor