The present study examines acoustic manifestations of the vocal fatigue in three groups of voice professionals (pronunciation teachers, professional speakers and tourist guides) who seem to be particularly susceptible to vocal loading. In the paper data collecting and the non-fatigue/fatigue speech corpus are described. The detailed acoustic analysis of the data obtained is presented. The results of the acoustic analysis showed a consistent dependency between acoustic parameters and vocal fatigue in terms of F0, jitter and shimmer values. The results can contribute to objective voice examinations and automatic voice pathology detection.