Although increasing evidence shows that mindfulness is positively related to mental health, the nature and mechanisms of this relationship are not fully understood. Based on previous research findings and suggestions, the authors of the current study hypothesized that decentering and nonattachment are 2 variables that mediate the relationship between mindfulness and psychological distress. A nonclinical, non-treatment-seeking sample of 308 students and employees from a middle-class, primarily Caucasian university filled out mindfulness, decentering, nonattachment, and mental distress measures online. Mediational analyses failed to support the hypothesis. Results suggest that mindfulness and nonattachment are independent predictors of nonclinical psychological distress and fully explain the effect of decentering on psychological distress. Results should be interpreted with caution and not generalized to clinical issues. A more comprehensive look into the mechanisms of mindfulness, especially with rigorous experimental, longitudinal studies, is warranted. The authors stress the importance of checking alternative, equivalent models in mediation studies.