Our objective was to understand the impact of motor and nonmotor symptoms of patients with early and middle stage Parkinson's disease (PD) on their spouses' caregiver strain and depression. A sample of 219 spouse caregivers of PD patients participating in a clinical trial was evaluated for six dimensions of caregiver strain and depression using the Family Care Inventory. Motor and nonmotor (i.e., psychological) clinical symptoms collected from PD patients as part of the clinical trial protocol were used as predictors. Seven hierarchical regression analyses were used to determine the contribution of the motor and nonmotor clinical symptoms in explaining variation in each of the seven caregiver‐dependent variables. Clinical symptoms explained 9–16% of the variance in caregiver strain and 10% of depression. Motor symptoms explained 0–6% of the variance and nonmotor psychological symptoms explained 7–13% of the variance in caregiver strain. Comparing our findings with literature that is deemed clinically relevant for patient symptoms that predict caregiver strain, we concluded that PD patient symptoms are important predictors of caregiver strain and depression. Patient nonmotor psychological symptoms have a much greater impact on caregiver strain and depression than patient motor symptoms. © 2008 Movement Disorder Society