The Štokavian dialect is one of the three dialects of the Croatian language and forms the basis of the Croatian standard language. The Dubrovnik idiom belongs to the East Herzegovinian Štokavian dialect. It is characterized by its dialectal coloring of vowels, especially the vowel /a/. The aim of this study was to describe the pronunciation of vowels in 10 native speakers from the Dubrovnik speech area using acoustic formant analysis. The analysis focused on the pronunciation of stressed vowels in isolated meaningful words and in isolated logatom pronunciations. The formant values of the vowels were compared with the formant values for the standard, neutral pronunciation of Croatian vowels from previous studies. The results showed certain deviations in vowel pronunciation in the Dubrovnik speech in both types of speech material. The smallest deviations were observed in female speakers for the vowels /o/ and /e/, while the largest deviations were noted for the vowels /a/ and /u/. In male speakers, smaller deviations were observed in the vowels /a/, /o/, and /i/, while the largest deviations were present in the vowels /i/ and /u/.