The following technical report is available from http://aib.informatik.rwth-aachen.de: Proceedings of the Young Researchers' Conference "Frontiers of Formal Methods" Thomas Ströder and Wolfgang Thomas (Editors) AIB 2015-06 The Young Researchers' Conference "Frontiers of Formal Methods" (FFM 2015) is a "singularity" - an event that is not part of a longer conference series, but organized following a nice coincidence of interests of several research groups in Germany and Austria. It all started with a loose promise given in 2010: When the second phase of the DFG research training group (Graduiertenkolleg) "AlgoSyn" started in Aachen, we promised to organize a final conference at the end of altogether nine successful years of work by and with doctoral students. In discussions between the speakers of closely related research training groups, it became then clear that all our doctoral students would gain most by a jointly organized conference. Five partners joined their forces: the DFG research training groups AlgoSyn (Algorithmic Synthesis of Reactive and Discrete-Continuous Systems), Aachen, PUMA (Program and Model Analysis), Munich, QuantLA (Quantitative Logics and Automata), Dresden & Leipzig, SCARE (System Correctness under Adverse Conditons), Oldenburg, and the Austrian Research Network ARiSE (Rigorous System Engineering).