Objective: Study examined perceptions of personal loss due to mental illness and social network characteristics among young adults with a psychiatric disability and their parents. Research directly compared young adults' and parents' reports of personal loss, social network structure and support, and interpersonal loneliness. Relationships between perceived networks, personal loss, and loneliness for adults and parents were examined. Method: Sixty young adults diagnosed with schizophrenia or bipolar disorder and their parents from 30 families completed individual, semistructured interviews that assessed social networks, loneliness, and personal loss due to mental illness. Results: Differences between young adults and parents were found in types of personal loss due to mental illness and the structure of their perceived networks. Parents reported larger networks with more family members than did adults, but no significant differences were found in perceptions of social support. Adults and their parents reported similar feelings of loneliness, but a differential pattern of relationships was found between perceived personal loss, network characteristics, and loneliness among adults and their parents. Conclusions: Study highlights importance of including both adults with psychiatric disability and their parents in family research. Comparing experiences of adults and parents can help to describe disruptions due to mental illness and perceived availability of social resources in the context of family life.