The development of concrete in the 19th & 20th centuries led to new possibilities and advancement in construction. Concrete was exploited to address the post-war needs for economical and faster construction. Significant reinforced concrete structures are recognized as cultural heritage. Long term durability problems present conservation challenges and the understanding of failure mechanisms is fundamental for restoration. The diagnosis of historic structures, materials investigation, monitoring and assessment are important steps towards the understanding of deterioration and appraisal of concrete heritage. Long-term effects of conservation and repair also need to be considered. The assessment of concrete heritage is addressed through military and industrial heritage concrete structures in Malta, including coastal structures in aggressive environments. A methodology for appraisal is proposed taking into consideration materials and structural performance and degradation mechanisms.peer-reviewe