The current study used a descriptive correlational design to examine the relationship between mindfulness and quality of life (QOL) among patients with schizophrenia (n = 160) and patients with major depressive disorder (MDD) (n = 161), controlling for demographic and clinical variables. Participants completed self-reported questionnaires regarding demographic variables, severity of depression, QOL, and mindfulness. Patients diagnosed with MDD had higher mindfulness scores than patients diagnosed with schizophrenia. Mindfulness scores were significantly associated with the severity of depression among participants. After controlling for the demographic variables and severity of depressive symptoms, mindfulness had a unique variance in QOL among patients with schizophrenia, but not among patients with MDD. The current study provides preliminary evidence regarding the role of mindfulness in improving depressive symptoms and the overall QOL among patients diagnosed with mental illness.