This study assesses the facet structure and psychometric properties of the Five Facet Mindfulness Questionnaire (FFMQ) with a heterogeneous clinical sample of individuals with mood and anxiety disorders. Various factor models of the FFMQ were submitted to confirmatory factor analyses (CFA). A four factor hierarchical solution, consisting of an overall mindfulness construct subsuming at least four factors, was adopted. Both internal consistency and convergent and discriminant validity were assessed. Along with demonstrating good internal consistency, the facets of the FFMQ were appropriately associated with other psychological constructs. Many mindfulness facets exhibited inverse relationships with emotion dysregulation, emotional avoidance, and psychological distress. The observe facet appeared to assume a role antagonistic to overall mindfulness within a clinical sample, as it exhibited a positive relationship with anxious arousal and no relationship with two other mindfulness facets. Findings support the notion of mindfulness as a multifaceted construct, the structure of which alters in the context of psychopathology.