This article is aimed to provide an analysis of the circumstances and problems related to Lithuania’s integration into NATO. It presents an overview of the path of Euro- Atlantic integration Lithuania has taken as well as the reasons behind the favourable outcome of NATO’s Prague Summit in November 2002, discusses factors which have had an impact on NATO enlargement and their interplay: a general development of the geopolitical landscape in Europe and Lithuania’s efforts to receive an invitation of membership. The context of NATO enlargement is used to review Lithuania’s security policy, relations with Russia, as well as the influence of Russia as a specific and exclusive factor in the processes of NATO enlargement. The article concludes with a summary of Lithuania’s foreign policy objectives and priorities for the post-Prague period.