The 4th International Workshop on Knowledge Discovery Using Cloud and Distributed Computing Platforms (KDCloud, 2013) provides an international platform to share and discuss recent research results in adopting cloud and distributed computing resources for data mining and knowledge discovery tasks. Synopsis: Processing large datasets using dedicated supercomputers alone is not an economical solution. Recent trends show that distributed computing is becoming a more practical and economical solution for many organizations. Cloud computing, which is a large-scale distributed computing, has attracted significant attention of both industry and academia in recent years. Cloud computing is fast becoming a cheaper alternative to costly centralized systems. Many recent studies have shown the utility of cloud computing in data mining, machine learning and knowledge discovery. This workshop intends to bring together researchers, developers, and practitioners from academia, government, and industry to discuss new and emerging trends in cloud computing technologies, programming models, and software services and outline the data mining and knowledge discovery approaches that can efficiently exploit this modern computing infrastructures. This workshop also seeks to identify the greatest challenges in embracing cloud computing infrastructure for scaling algorithms to petabyte sized datasets. Thus, we invite all researchers, developers, and users to participate in this event and share, contribute, and discuss the emerging challenges in developing data mining and knowledge discovery solutions and frameworks around cloud and distributed computing platforms.