Singers appear to experience health benefits from singing, but their art makes physical demands that may leave them prone to health problems. The study sought to measure singers' immunocompetence under practice and performance conditions. Salivary IgA and cortisol measurements were assayed from multiple pre-post saliva samples obtained from 10 solo singers as they rehearsed and performed repertory in a college conservatory during a 10-week period. Confirming previous research on choirs, there was a significant increase in S-IgA after singing, and the effect was mediated by positive emotions of well being and feeling "high." The extent to which singers reported that they were usually stressed while singing was significantly correlated with decreases in S-IgA. Satisfaction with performance correlated significantly with a decrease of cortisol after singing. In a regression analysis, the best predictive model for upward change in SIgA included two significant variables from the questionnaire: feelings of well being and relative lack of concern with artistic identity (p < 0.018). These findings suggest that preserving solo singers' positive emotions during singing may not only maintain their enjoyment of singing, but may also improve their immunocompetence in response to health risks.