Pathological gambling involves multitudinous costs related to financial, legal, and public health care aspects, as well as to specific psychological disorders. Despite the overall evidence suggesting that comorbid disorders represent a risk factor for pathological gambling, there is scant evidence on the appropriate treatments for gamblers with such disorders. In this context, metacognitive therapy is an interesting approach because it considers psychological disorders as a result of the activation of perseverative cognitive processes and attentional strategies in response to inner events. Several studies report that metacognition is associated with different psychological problems. This study investigated the relationship among comorbid disorders, metacognition, and pathological gambling. 69 pathological gamblers at the first hospital admission and 58 controls drawn from general population (matched for age, gender, education) completed a battery of self report instruments: Symptom Checklist-90-R, Metacognition Questionnaire 30, South Oaks Gambling Scale. Compared to controls, pathological gamblers showed higher level of comorbid symptomatology and metacognition. Correlation analyses showed that: comorbid symptomatology and metacognition were positively and significantly correlated with pathological gambling; metacognition was positively and significantly associated with comorbid symptomatology. Mediation analysis indicated that dysfunctional metacognitive strategies could have an indirect effect on pathological gambling mediated by concurrent psychological disorders. These findings provide some implications for gambling treatment programs: pathological gamblers should be screened for psychiatric disorders, and metacognitive therapy could be considered a correct treatment of pathological gamblers. Metacognitive therapy might lead to the reduction of the pathological gambling by the diminishing of the concurrent psychological disorders.