During its evolution, the Zemplinic basement underwent a polyphase of regional deformation. Distinctions between pre-Variscan and Variscan events have been widely discussed in previous studies. In order to assess the polyphase, detrital monazites from four Pennsylvanian–Permian sandstones, as well as one Permian vitroclastic tuff, were dated using the Th–U–Pb electron-microprobe method. In total, four monazite generations were recognized in the analyzed sediments and associated acid volcaniclastic rock: Cambrian–Ordovician, Mississippian, Pennsylvanian, and Cisuralian. All monazite phase analyses can be categorized as monazite-(Ce), with the extent of cheralite versus huttonite exchange. Detrital monazites from the Zemplinic Pennsylvanian–Permian sediments were determined by monazite dating and ­subdivided to several age populations. Early Paleozoic age population was recorded in a relatively large range, from 507 to 435 Ma, with a calculated average age of 461±6.7 Ma. These ages roughly correspond to previously published detrital zircon (SHRIMP) age determinations (Middle/Late Ordovician with the age peak ca. 459 Ma) from the same stratigraphic horizons. Nevertheless, the majority of detrital monazite age data span between 360 and 300 Ma, thus forming significant spikes at 320 and 330 Ma and resulting in a calculated average age of 327±1.6 Ma. This population of detrital monazites indicates the predominance of Bashkirian–Moscovian tectonic events in the assumed source area. Derivation of monazites from the Kasimovian–Gzhelian synsedimentary acid volcanism is indicated by ages in the range of 308–299 Ma. Interestingly, only a few monazite grains derived from the volcaniclastic rock yield the age indications for the Permian extensional thermal re-heating, which has long been associated with the manifestations of acid volcanism (270–290 Ma). The monazite age data from the Zemplinic Pennsylvanian-Permian sedimentary formations reflect the main stages of tectonothermal progress in the Zemplinic crystalline basement.