In spite of strong competition of synthetic materials (including PVC, EPDM), bitumen remains the major component of most waterproofing materials. It makes up approx. 80% by weight of the final product. The characteristics of bitumen mix have a decisive impact on the quality of the final product. During storage, transport, manufacturing and installation of waterproofing materials, bitumen is subject to ageing. As a result of the ageing process the characteristics of bitumen waterproofing materials deteriorate, roofing membrane becomes more rigid and cracks. The damaged waterproofing layer ceases to perform its function; it does not protect the building envelopes against water penetration. The development of organic chemistry allowed the synthesis of a number of modifying substances used for chemical modification of bitumen. Among the most promising are heterocyclic organic compounds belonging to the group of imidazolines. The article presents the results of preliminary laboratory tests of bitumen modified jointly by SBS and imidazoline. The objective of the study was to find a new type of bitumen modifier (hybrid modifier) synergically combining the advantages of both types of presented modifications.