The economic history of Uruguay throughout the 20th century, and more especially its second half, is characterized by a long-term economic decline. From the end of the Second World War, economic institutions and the policies adopted were unable to create a favorable climate for growth and development. This article presents evidence to support the idea that institutional factors played a part in the weak GDP growth and the high level of cyclical volatility between 1920 and 2001. Some factors stand out as particularly relevant: the weakening of governments' political power, increasing fragmentation of the political system, an excessively discretional monetary policy and the existence of opportunistic political cycles in macroeconomic policies.