One of the most important inputs in the building of a structure is financial sources. The correct guidance of these sources is distinctive for structural costs. The decision to use the materials determined by the architect is important in determining the cost. It is important that the material usage decisions are given correctly and thus the structural cost analysis is evaluated based on material. Structural cost is an area in which proper solutions can be developed throughout the process starting from the first stage of the design. The effect of material selection on structural cost has been examined in this study using important structures of significant architects as examples. The structures used in the study have been determined as; Farnsworth House, Fisher House, Glass House, Koshino House, Schröder House, Villa Kokkonen, Villa Savoye. Selecting examples of modern architecture in different countries was a significant criteria in this selection process. Because it was observed that local materials were used in every building according to the location. The use of local materials as well as the use of materials such as ferroconcrete or glass is a factor that affects structural cost. First, the unit prices of the current materials selected were calculated for the selected buildings. Afterwards, material selections suited to the structure were selected from among the alternative materials used today and cost was calculated using the unit prices of these new materials. It was determined that material selection has significant effects on structural cost. It was aimed to put forth the importance of materials in cost determination via selection of the sample buildings and the material study carried out. It is hoped that this study will contribute to the field of structure regarding the effects of material selection on the cost.