The question of vowel intelligibility as a function of F0 is still a matter of debate. Above all concerning vowel sounds produced at F0s exceeding vowel related statistical F1 in citation-form words (‘oversinging’ F1), it is unclear whether vowel category perception inevitably shifts towards the neighboring category with a higher F1 or can be maintained in such cases. In this study, we tested listeners’ perception of the long German vowels /i-y-e-ø-ε-a-o/ produced by a trained female speaker in the context of minimal pair words (/l-V-gen/) at nine F0-levels between 220 and 880 Hz. Results showed that vowel identification was maintained > 80% up to F0=740 Hz for /e-ø-ε/ and up to F0=880 Hz for /i-y-a-o/. Thus, vowel identification could be maintained in cases of F0 significantly exceeding F1. The role of neighboring vowels, vowel duration, and other productional and acoustical aspects relevant for vowel perception at different F0s is discussed.