Introduction: Hearing loss (HL) strongly impacts communication abilities and impairs social interactions. Moreover, it modifies the vocal parameters of affected patients. The effects of hearing rehabilitation through hearing aids (HA) on the vocal production of patients suffering from HL have not been thoroughly analyzed in the literature. The aim of this study was to use the ambulatory phonation monitor (APM), a portable vocal dosimeter, to evaluate the variations in the vocal production of a group of patients suffering from moderate-to-severe HL treated with HA and the relationship between such modifications and quality of life (QoL). Materials and Methods: Twenty-six patients suffering from a variable degree of HL and treated with HA have been enrolled. Each of them underwent an evaluation before and 4 months after rehabilitation with HA. The analysis of daily voice production was carried out with the APM, while subjective QoL data were collected through the Speech, Spatial, and Qualities questionnaire (SSQ) and the International Outcome Inventory for Hearing Aids (IOI-HA). The differences in phonatory measurements and subjective evaluations before and after HA rehabilitation were assessed using Wilcoxon signed rank test. The Spearman correlation test was used to analyze the correlation between phonatory measurements, auditory measurements, and SSQ scores. Results: Significant differences in the APM parameters before and after HA rehabilitation were found. After 4 months of HA use, we recorded a significant increase in phonation time and percentage of phonation time and a significant decrease in average amplitude in dB SPL. We also found a significant increase in the SSQ scores after HA rehabilitation. Finally, we were able to detect low but significant correlations between phonatory measurements and SSQ results. Conclusions: The APM proved to be a useful instrument in the evaluation of the benefits of HA and its measurements can be used as indicators of the participation in communication and social life of patients with HL, which are strongly related to QoL.