The regional dialects of Modern Greek are varieties that give to the language a special diversity, rich in linguistic features. The present study moves towards the laboratory-based documentation of vowel realization in different dialects at the same time. It also aspires to contribute-as much as it is possible-to the development of a phonetic atlas of the Greek-speaking world, through the acoustic analysis of four regional dialects, which come from the northern part of Greece, namely Corfu, Ioannina and Arta from Epiros, Kozani and Evros.The acoustic analysis of the dialects focuses on their vocalic systems, which comprise the 5 common vowels of Greek, namely /i, e, a, o, u/. The aim of this study is to point out the similarities and differences in the behavior of the four systems. The factors under analysis for effects on the realization of vowels were speaker gender, vowel stress, the phonetic environment of vowels and prosodic factors relating to the position of vowels. Through the thorough analysis of the variation factors, the study goes beyond a mere comparisons of the dialects, and tries a new, comprehensive methodological approach of the phonetic realization of vowels.