The male calling song of Poecilimon fussi, an Eastern European bush-cricket species, is described for the first time and fully illustrated by oscillograms at several speeds. The calling songs of 18 males (9 from Transylvania [Rumania] and 9 from Hungary) have been analysed. The male calling song of P. fussi is a long syllable-sequence in which syllables follow each other in quick succession. During the whole song two types of syllable can be observed. Type "A'' is a single pulse-series lasting for 150-200 ms at 22-23 °C, composed of 40-50 pulses without any additional, isolated pulse at its end. In type "B'' a main pulse series of 100-150 ms duration (22-23 °C), containing 60-70 pulses is followed by a single (or a few) additional pulsels). In the course of the whole song a cyclic alternation of two phases can be observed. Phase 1 is composed solely of "A'' type syllables while phase 2 is constituted exclusively by "B'' type syllables. The transition between the consecutive phases is quite sudden: there are only a few syllables showing transitional characteristics. While the pulse repetition patterns of "A'' and "B'' type syllables are not unusual in this genus, this kind of two-phased song is unique amongst the Poecilimon species in which the songs have been described.