This study evaluates and contrasts the management practice and the performance that characterise Environmental Impact Assessments (EIA) in Italy and in the UK. The methodology relies on the investigation of six carefully selected case studies, critically reviewed by referring to EIA and project design information, as well as collecting the opinion of key project participants. The study focuses on the construction industry and on specific key sectors like infrastructure for transport and renewable energy and commercial and tourism development. A main term of reference for the analyses has been established by critically reviewing international literature so as to outline common good practice, requirements for the enhancement of sustainability principles and typically incurred drawbacks. The proposed approach enhances transfer of knowledge and of experiences between the analyzed contexts and allows the provision of guidelines for practitioners. Distinctive differences between the UK and the Italian EIA systems have been detected for pivotal phases and elements of EIA, like screening, scoping, analysis of alternatives and of potential impacts, definition of mitigation strategies, review, decision making, public participation and follow up.