This article studies factors that affect stability of supply of natural gas. It examines the relative influence of political relations between the involved states on the stability of supply. The article identifies the factors that affect the propensly of a state to use disruption of natural gas supply in order to promote foreign policy goals. The article is based on the study of thirty five supply relations and two case studies. The article claims that disruption of supplies can be initiated not only by supplier states, but transit and consumer states. It claims that natural gas supply relations generally take three forms: neither side is dependent on the gas trade, one side is dependent on the gas trade, or the sides are interdependent in the gas trade. Cases of significant asymmetry of the degree of dependence in the gas trade are most likely to be exploited by the less dependent party for foreign policy gain: The article claims that the prevailing political relations between gas trading states are only one of the factors affecting the stability of supply. (C) 2012 Elsevier Ltd. All rights reserved.