Less is known about the experiences of older adults (65+ years of age) with co-occurring mental health and alcohol and other drug use disorders (dual diagnosis) than is known about the experiences of their younger counterparts. This exploratory qualitative study sought to interview individuals receiving case management from an inner Melbourne community mental health service to determine their experiences of living with dual diagnosis and explore their interactions with mental health and addiction treatment, and general medical services alike. Six older adults with a dual mental health and substance disorder agreed to participate in a semi-structured interview process and provided their perspectives about living with complex mental illness and alcohol and other drug use. Several key themes emerged throughout the interview process, mirroring the notion of dual diagnosis being a complex phenomenon involving a number of interrelated factors: these include medical complexity, poor service engagement and long-term use of alcohol and other drugs. Interviews also demonstrate the challenges inherent in providing care to this cohort, with the participants frequently describing their experiences with services as being fraught with difficulty. The increased understanding of the perspectives of older adults with dual diagnosis provides the foundation for further research into this population in addition to influencing future nursing care provided to this cohort.