It is hard to automatically find a semantically meaningful web service composition over a huge collection of web services available on the web. However, recent results in semantic web service research and technology could be effectively used within some specific domains. E-government is one of the sectors that need horizontal integration. Therefore, semantic web services and their composition become necessary and applicable in this domain. The paper proposes a semantic method of automatic composition of e-government services. It uses domain ontologies presented in OWL, semantic web services described in SAWSDL, quality of service (QoS) characteristics, ontology reasoning and AI planner in order to automatically provide service plans that could be presented in some service execution language. The approach is motivated by a case study from the domain of the Estonian state information systems.