Very little is known about the coordination of muscles involved in mammalian vocalization at the level of single neurons. In the present study, a telemetric single-unit recording technique was used to explore the ventrolateral pontine brainstem for vocalization-correlated activity in the squirrel monkey during vocal communication. We found a discrete area in the reticular formation just above the superior olivary complex showing vocalization-correlated activity. These neurons showed an increase in neuronal activity exclusively just before and during vocalization; none of them was active during mastication, swallowing or quiet respiration. Furthermore, the neuronal activity of these neurons reflected acoustic features, such as call duration or syllable structure of frequency-modulated vocalization, directly. Based on these findings and previously reported anatomical data, we propose that this area serves as a vocal pattern generator for frequency-modulated call types.