Devastating floods are a rare and unique phenomenon that prompts an in-depth hydrological analysis. The paper addresses the May 2014 flooding of the Bosna River. In May 2014, flooding occurred as a consequence of precipitation that continuously fell for several days over the Sava River and its lower reach tributaries in the territories of Croatia, Bosnia and Herzegovina, and Serbia. The precipitation in some places exceeded a 5000-year return period and discharges a 100-year return period.