This study attempts to acoustically characterize the most common filled pause vocalizations (or vocalic fillers) in spontaneous speech in European Portuguese: the near-open central vowel [ɐ] and the mid-central vowel [ə]. For this purpose we analyzed the spectral information of the vocalic fillers by estimating their first two formant frequencies as well as their duration properties. The vocalic fillers are taken from a large corpus of European Portuguese broadcast news' speech. We also compared the vocalic fillers with lexical vowels possessing similar timbre. No formant variation trend was attained for the vocalic fillers and a great overlap of formant values is observed. These results provide a base of information for understanding the most common vocalic fillers in European Portuguese spontaneous speech.