Purpose: Oxytocin and arginine vasopressin are associated with different aspects of the stress response. As stress is regarded as a risk factor for vocal symptoms, we wanted to explore the association between the oxytocin receptor gene ("OXTR") and arginine vasopressin 1A receptor gene ("AVPR1A") single-nucleotide polymorphisms (SNPs) and vocal symptoms. We also wanted to explore whether such effects might be mediated by cortisol because oxytocin and vasopressin are associated with cortisol levels. Method: A population-based sample (N = 657) of Finnish twins (born 1961-1989) completed a web questionnaire on the occurrence of vocal symptoms. A total of 170 participants submitted saliva samples for hormone analysis. A total of 20 "OXTR" and "AVPR1A" SNPs were analyzed. Results: Three "OXTR" polymorphisms (rs2270465, rs2268493, rs7632287) and 2 "AVPR1A" polymorphisms (rs1587097, rs1042615) showed nominal effects (p < 0.05) on vocal symptoms, of which 1 (rs1587097) remained significant after correcting for multiple testing (p = 0.003). We found potential mediation of the effect of the "OXTR" rs2268493 polymorphism on vocal symptoms through levels of cortisol. Conclusions: The associations between variants of "OXTR" and "AVPR1A" and vocal symptoms indicate that oxytocin and vasopressin might influence vocal symptoms. The effect of oxytocin seems to be partly mediated through cortisol actions.