The 4th International Workshop on Traffic Monitoring and Analysis (TMA 2012) was an initiative of the TMA COST Action IC0703 "Data Traffic Monitoring and Analysis: Theory, Techniques, Tools and Applications for the Future Networks" (http://www.tma-portal.eu/cost-tma-action). The COST program is an intergovernmental framework for European coperation in science and technology, promoting the coordination of nationally funded research on a Euripean level. Each COST Action aims at reducing the fragmentation in research and opening the European reserch area to cooperation worldwide. Traffic monitoring and analysis (TMA) is and importan research topic within the field of computer networks. It involves many reserch groups wordwide that are collectively advancing our understanding of the ever-evolving Internet. The goal of the TMA workshop is to open the COST Action research and discussions to the worldwide community of researchers working in this field. Affer a preliminary selection by the Workshop Chairs, 31 valid submissions were admitted to the review process, which finally resulted in the acceptance of ten full papers and eight short papers to the final program. Each paper was carefully reviewed by at last three members of the Technical Program Committee. //ir
