Politics and industry increasingly request comprehensive ex-ante decision support from a sustainability perspective in complex strategic decision situations. Several approaches have been introduced in the last years to increase the comprehensiveness of life cycle based assessments from covering only environmental aspects towards covering all sustainability aspects. This way, (environmental) life cycle assessment (LCA) has been extended towards life cycle sustainability assessment (LCSA). However, a practical application in ex-ante decision support requires additional features and flexibility that do not exist in the newly devised frameworks. Our methodology of integrated life cycle sustainability assessment (ILCSA) builds upon existing frameworks, extends them with features for ex-ante assessments that increase the value for decision makers and introduces a structured discussion of results to derive concrete conclusions and recommendations. At the same time, the flexibility allows for focussing on those sustainability aspects relevant in the respective decision situation using the best available methodology for assessing each aspect within the overarching ILCSA. ILCSA has so far been successfully applied in five large EC-funded projects. We discuss our methodology based on a concrete application example from these projects. (C) 2015 Elsevier Ltd. All rights reserved.