The purpose of this study is to thoroughly examine the conditions leading to the development of a mesoscale convective complex (MCC) on 24 May 2009 that affected the western and southern Balkan Peninsula, its features and the manifestation of its activity at the surface. To this end, data from a variety of sources were used, such as weather maps, surface records and upper-air soundings, a hailpad network, satellite, lightning, precipitation and radar data. First, the evolution of the system was described, in terms of the track, timing, and areal extent. Second, the synoptic and thermodynamic environment that favored its development was studied. Special features at the surface, such as a cold pool and a mesohigh, were documented by surface observations. Finally, successive satellite, lightning and radar imagery revealed the organization of the system. All data together document well the categorization of this system as an MCC.