Due to the process of globalisation in the world economy, business cycles are becoming increasingly interdependent. Under globalisation, emerging countries have increased their economic weight in the world, at the same time conforming to the economically developed countries. The new structure of the global economy causes significant implications for business cycles in most countries of the world . Among the factors that contribute significantly to greater interdependence of business cycles are rapidly growing international flows of foreign investment (i.e. financial integration). The purpose of this paper is to analyse the impact of international capital flows on the synchronisation of business cycles in Poland and the European Union in the period of 2005-2013. The author uses a research method based on the study of relevant literature on macroeconomics and international finance, as well as econometric methods (Vector Autoregression Model -VAR). The results of empirical studies indicate that the increase in capital movements does not necessarily lead to an increase in business cycle synchronisation in the analysed economies. The impact of the growth of capital flows on business cycle synchronisation depends not only on the intensity of capital movements, but mainly on the structure of capital flows.