Concrete, as a material, has a relatively high compressive and low tensile strength, so concrete structures are vulnerable to cracking. Cracks have influence on the durability and the load-bearing capacity of the structure and therefore regular visual inspection and crack analysis are required. In the framework of this thesis, evaluation of cracks on three concrete bridges across Sava River in Zagreb is provided in two stages: preliminary, based on the theoretical knowledge and using software developed by Japan Concrete Institute (JCI). Evaluation of cracks on each bridge includes: (i) collecting data on bridge design, construction and maintenance; (ii) visual inspection; (iii) measurements of crack geometry using non-destructive methods; (iv) determination of crack cause; (v) decision on needed repair and/or strengthening and (vi) selection of repair and strengthening methods. Based on the provided analysis of cracks on the selected bridges, it can be concluded that the JCI software is helpful tool for concrete cracks evaluation, but engineer's knowledge and experience are a key factor in the analysis of cracks on concrete structures. The crack catalogue is created based on crack causes represents an additional contribution of this thesis.