Abstract. Service Based Systems, composed of Web Services (WSs), offer promising solutions to software development problems for companies. Like other software artefacts, WSs evolve due to the changed user requirements and execution contexts, which may introduce poor solutions-Antipatterns-may cause (1) degradation of design and quality of service (QoS) and (2) difficult maintenance and evolution. Thus, the automatic detection of antipatterns in WSs, which aims at evaluating their design and QoS requires attention. We propose SODA-W (Service Oriented Detection for Antipatterns in Web services), an approach supported by a framework for specifying and detecting antipatterns in WSs. Using SODA-W, we specify ten antipatterns, including God Object Web Service and Fine Grained Web Service, and perform their detection in two different corpora: (1) 13 weather-related and (2) 109 financial-related WSs. SODA-W can specify and detect antipatterns in WSs with an average precision of more than 75% and a recall of 100%.