Abstract: A complex emergency can be defined as a humanitarian crisis which occurs in a country, region, or society where there is a total or considerable breakdown of authority resulting from civil conflict and/or foreign aggression; a humanitarian crisis which requires an international response which goes beyond the mandate or capacity of any single agency. This article evaluates the viability of the United Nations (UN) peacekeeping operations in complex emergencies in terms of its adherence to the principles of impartiality/ neutrality, consent and the non-use of force except in self-defence situations. Particular attention is given to the characteristics of the complex emergencies, and the changing nature of conflicts. The article uses examples drawn from the different cases of UN peacekeeping in failing and failed states in Africa and beyond. The article concludes that it is unreasonable to expect UN peacekeeping operations to adhere to the principles of consent, impartiality and non-use of force except in self-defence in cases of complex emergencies. A qualitative research approach was used to arrive at these assertions.