The selection of environmentally responsible building products and systems is a central aspect of sustainable building. Wood has been used as a building material for centuries. Wood is strong, lightweight, very easy to use and to manufacture into new products. Wood also possesses positive environmental attributes ; not only is wood the single major renewable building material, but it also requires less energy to manufacture than any other building material . Wood is also a renewable material. It can be used for construction, furniture, food handling, packaging, pallets and transport applications. At the end of its first life, wood or a wood-based product can be reused, recycled or used as a carbon-neutral source of energy. Respecting for the carbon cycle will produce greatest benefits not only from a longer period of carbon storage, but also from the energy and finite resources saved from the production of alternative fossil-based materials. Lightweight glulam timber structure is analyzed. Span of the structure is 33 meters. Static system is three hinged system with steel truss. Total length of the building is 65 meters. Purlins are simple supported beams with span of 7.15 meters (span between the main girders). Very detailed finite element model of the structure is made. Concrete structure has the same dimensions as the timber (total length of the structure, span and spacing between main girders are the same as described earlier). Material chosen is concrete C30/37. Main girder is prestressed beam 35x160 cm. Structures are analyzed using modal response spectrum analysis according to Eurocode 8 (EN 1998). As it is intended to compare various spectrum curves, all ground types defined in EC8 are analysed (A, B, C, D and E). Damping is assumed to be 5% for concrete structure and 7% for timber structure. Seismic load is applied both horizontally and vertically. Linear time history analysis is made by using three real accelograms representing earthquakes in Croatia. The earthquakes are selected from two basic criteria: magnitude of 6 or greater and peak horizontal acceleration of 2 m/s2 or greater. All ground types defined in EC8 are analysed (A, B, C, D and E). For the purpose of calculation total base shear, square root of sum of squares (SRSS) method is used. Results and discussion about response spectrum and time history is given. This paper shows that lightweight structures like timber structures have excellent response during seismic action (forces and displacements are rather small so structure remains elastic). Given all the advantages of these structures, authors suggest using timber structures in seismically active regions.