Together with the emergence of strong executive presidencies and the frequency of coups d'Etat, the single party is one of the striking features of the political development in Africa South of the Sahara since 1960. More than half the countries of the continent are presently under one-party rule. This article attempts to analyse the origins, recent developments, and perspectives in the field of African single-party states. Sameelements favourable to the emergence of this phenomenon were the colonial heritage, the precolonial tradition, and the aura of legitimacy of the national liberation movements. Several techniques were usedby African leaders to impose rule by one party; distinction is made between political, legal and institutional, and authoritarian means. African leaders have relied on several justifications to rationalise the introduction of such regimes: economie development, national unity and nation-building, the absence of class-differentiation, the unanimitarian tradition, and the need to give constitutional recognition to a de facto situation. A critical analysis shows that these arguments do not, in general, withstand closer examination. The conclusion is that the single-party «ideology» serves mainly to protect the hegemony of a small and privileged political class of rulers against challenge of its position. As far as perspectives are concerned, three possibilities seem to be developing simultaneously: the Party-State, the no-party state, and the multi-party state. It is argued in a conclusion that the single-party state need not be undemocratic; some conditions for a democratic one-party system are set forth.