The project named ‘Evaluation of Ecological Criteria for Cotton Textile Products’ which was carried out by Boğaziçi University Sustainable Development and Cleaner Production Center is elected as ‘one of the best applications in the national scale’ in the area of ‘Sustainable Development’ and ‘Green Economics’ in Rio +20. The aims of the project were (a) to quantify and evaluate the major environmental impacts associated with the whole life cycle of conventional T-shirt using Life Cycle Assessment (LCA) methodology, addressing impact categories of acidification, global warming, photochemical ozone formation, aquatic and terrestrial eutrophication, (b) to reduce/minimize the negative environmental impacts through development of an alternative T-shirt production system (here after mentioned as ECO T-shirt) regarding sustainable production principles, and (c) to compare conventional T-shirt and ECO T-shirt considering selected environmental performance indicators. Potential environmental impacts are assessed considering cultivation and harvesting, ginning, spinning, knitting, wetprocessing, service/use and disposal stages.