Contributions of informal caregivers to adherence among chronic obstructive pulmonary disease (COPD) patients remain understudied. This study aims to evaluate the association between caregiver presence and adherence to medical recommendations among COPD patients. Three hundred and seventy-four COPD patients were asked whether they had a caregiver. Medication adherence was assessed using pharmacy refill data. Smoking status was based on patient self-report. One-way ANOVAs and chi-square analyses were performed controlling for age and number of illnesses. Compared with the "no caregiver" group, antihypertensive medications adherence was higher in the "spousal caregiver" (0.68 vs. 0.81; 95% CI=0.04 and 0.22) and "non-spousal caregiver" (0.68 vs. 0.80; 95% CI=0.03 and 0.22) groups; long-acting beta agonist adherence was higher in the "spousal caregiver" group (0.60 vs.0.80; 95% CI=0.05 and 0.43). Patients in the "spousal caregiver" group had fewer current smokers compared with the "no caregiver" (χ(2)=16.08; p<0.001) and "non-spousal caregiver" (χ(2)=5.07; p<0.05) groups; those in the "non-spousal caregiver" group reported fewer smokers than the "no caregiver" group (χ(2)=4.54; p<0.05). Caregivers, especially spouses, may improve adherence in COPD. Future interventions may target patients without caregivers to optimize COPD management.