The article gives the definition and classification of socio-economic crises. Socio-economic crises are often preceded by financial crises. It is shown the view of foreign researchers on the factors that cause financial crises. «Bubbles» and credit booms become the common causes of economic crises. This article examines types of financial crises. Distinctive feature of modern crises is contagion effect. With the help of an early warning system crisis can be identify beforehand. There is obviously a great benefit in knowing whether and if so when a crisis may occur: it can help put in place measures aimed at preventing a crisis from occurring in the first place or limiting the damage if it does happen. Development of includes various crisis indicators. The paper presents the view of four early warning systems: signal approach, probit model, composite indicators of The Organisation for Economic Co-operation and Development (OECD) and Purchasing Managers’ Index.