Their nature and functions make political parties central to democratic governance especially in the new democracies of Africa that face the challenge of building strong and enduring democratic institutions. It is accepted that the existing trend in most of these democracies of one big party dominating the political space weakens democracy and undermines its prospects for consolidation. Big parties-usually the ruling ones-exhibit tendencies such as absence of internal democracy that are antithetical to democratic governance. While observations such as these are incontestable, there is little understanding into the nature, character, ideology, and internal structure of big parties generally. In this article, I attempt to address this concern. Specifically, I examine the nature, structure, and ideology of the Peoples Democratic Party (PDP), Nigeria's ruling party at the federal level with considerable strength at local level between 1999 and 2015. Relying on data obtained from multiple sources, I investigate the process of its formation, the nature of its ideology, internal organization, its electoral strength, and how absence of internal democracy contributed significantly to its defeat in 2015 general elections.