It has been hypothesized that anger expression may be associated with increased salivary immunoglobulin A (sIgA) levels, which is associated with decreased somatic symptoms, and therefore anger expression may be associated with reduced somatic symptoms in intimate partner violence (IPV) perpetrators. This study tested the potential mediating effect of sIgA levels on the relationship between anger expression and respiratory and gastrointestinal symptoms in IPV perpetrators and non-violent controls. The sample consisted of IPV perpetrators (n = 19) and controls (n = 21). Saliva samples were collected for assessing sIgA levels. The State-Trait Anger Expression Inventory–2 was used to assess anger expression and the Revised version of the Somatic Symptoms Scale developed by Sandín and Chorot to measure somatic symptoms. High anger expression was associated with low levels of respiratory and gastrointestinal symptoms in IPV perpetrators mediated through high sIgA levels but the same was not true for non-violent controls. This finding supports the hypothesis that for IPV perpetrators, anger expression may be physiologically and psychologically rewarding. Future research examining other immunological parameters is needed to further test this hypothesis. Such effort may illuminate why some IPV perpetrators continue to use violence against their partners.