The temporary Pollino Seismic Experiment, FDSN network code 4A, monitored the earthquake swarm in the Pollino Range region, Italy, between November 2012 and September 2014. The region is located at the transition from the Southern Apennines chain to the Calabrian arc. Striking a volume of about 20x20x15 km, the swarm started in October 2010, culminated in an Mw=5.2 event on 25 October 2012, and has continued since with a variable rate of activity. The area represents a seismic gap as there are no documented historical M>6 earthquakes during the last thousand years. The tectonic structures of the area are poorly known. The experiment was part of a collaborative effort made by the German Research Centre for Geosciences (GFZ) and the Istituto Nazionale di Geofisica e Vulcanologia (INGV) within the framework of the NERA and CCMP-Pompei projects. The 4A network consisted of 9 stations including 6 short-period and 3 broadband instruments, provided by GFZ. The permanent seismic network was complemented by the 9 GFZ stations and 5 IV stations temporarily installed by INGV. The short-period stations had Mark L-4C3D sensors with EDL digitizers. The broadband stations were equipped with STS2.5 seismometers and RefTek RT130S digitizers. Five short period and one broadband (CSA0 to CSA5) were installed in a small-aperture array in the west of the range. The other three stations (broadband: CSB, CSC and short period: CSD) were installed around the swarm area. The array and the network stations recorded in continuous mode at 200 Hz and at 100 Hz, respectively. The sensors were buried in the ground at 0.5 m depth except for CSB and CSD which were installed on the surface. High-precision station coordinates were obtained by using differential GPS measurements. The data have been used to analyze the earthquakes and seismogenetic structures and to discern the characteristics of the swarm sequence.