To compare the health conditions and health care costs of family members of patients diagnosed with a Major Depressive Disorder (MDD) to family members of patients without an MDD diagnosis. Using electronic health record data, we identified family members (n=201,914) of adult index patients (n=92,399) diagnosed with MDD between 2009 and 2014 and family members (n=187,011) of matched patients without MDD. Diagnoses, health care utilization and costs were extracted for each family member. Logistic regression and multivariate models were used to compare diagnosed health conditions, health services cost, and utilization of MDD and non-MDD family members. Analyses covered the 5years before and after the index patient’s MDD diagnosis. MDD family members were more likely than non-MDD family members to be diagnosed with mood disorders, anxiety, substance use disorder, and numerous other conditions. MDD family members had higher health care costs than non-MDD family members in every period analyzed, with the highest difference being in the year before the index patient’s MDD diagnosis. Family members of patients with MDD are more likely to have a number of health conditions compared to non-MDD family members, and to have higher health care cost and utilization.