Because caregivers’ monitoring of care recipients’ mental health status likely facilitates provision of needed forms of assistance, the current study examines relationship factors associated with agreement in caregiver- and recipient self-reports of recipients’ mental health status. Participants were former or current injection drug using persons with HIV/AIDS and their main caregivers (N = 258 dyads). Care recipients completed the Center for Epidemiologic Studies Depression scale and caregivers responded to a single item rating their recipients’ mental health. Nearly two-thirds (64.7 %) of dyads agreed on care recipients’ mental health status (κ = .26, p < .001). More secondary stressors of care, less reciprocity, and care recipients’ greater physical limitations, substance use, and younger age predicted greater agreement on recipients’ having poorer mental health. Greater secondary stressors and lower income were associated with less agreement on care recipients’ mental health. Findings, which suggest that promoting reciprocity and alleviating secondary stressors of caregiving may help facilitate these caregivers’ improved assessment of their care recipients’ mental health status, have implications to dyadic approaches to promote drug users’ HIV health outcomes.