The report compiles existing information about materials used for designing a top cover construction pursuant to Landfill Directive 1999/31/EC. The report includes a short review of existing requirements on top liners, especially in the Nordic countries.Accepting waste materials in top cover requires reliable information of both the technical and environmental properties. Important properties of waste material are listed, and factors to be considered in evaluating the functionality of the whole top cover construction are discussed. Key points in the evaluation of the suitability of waste materials in top cover are: the waste material fulfils the quality requirements and functions of the whole construction the quality variations of key properties are known and acceptable the long-term behaviour of the waste material is evaluated through pilot studies and proved reliable. This report describes the characteristics of the most typical waste materials used for designing top cover constructions. Moreover, a summary of Nordic studies on potential waste materials for top cover has been collated.