The series of Workshops on Software Services (WoSS) is dedicated to recent significant developments in the field of software services. WoSS intends to be an open forum for academics, practitioners, and vendors, allowing them to discuss the current trends and scientific and technological challenges, such as service quality assurance, adaptability, reliability, interoperability, and automating service-oriented application construction and management. The first three editions of this forum were organized with the support of the FP7-ICT SPRERS project, with the aim to highlight the achievements of the on-going European collaborative projects subscribing to FP7-ICT programme and the activities of the teams from new member states in software services area. The fourth edition is dedicated to Cloud and Grid Applications for Science and Industry and is supported by the FP7-ICT mOSAIC project.