Introduction: Postpartum depression negatively affects a woman's quality of life and the development of a relationship with her child, which can have far-reaching consequences on the cognitive, behavioral and emotional development of the child. Etiology includes genetic predisposition, sudden hormonal changes, and sociodemographic factors. Case report: A 28-year-old patient, married, mother of a one-month-old boy. She graduated from the High school of economics, unemployed. She appears in the family medicine clinic due to chronic fatigue and bad mood, at the insistence of her husband, who thinks that she needs professional help. She grew up in a harmonious family. He gets along well with his wife, there are no existential problems. It denies previous illnesses. Neat appearance, inconspicuous posture and behavior, psychomotor diskette slowed down, more sparse spontaneous verbalization, slightly compromised volitional instinctual dynamisms, lowered basic mood. In the laboratory findings, hypothyroidism with elevated thyroid peroxidase antibody and antithyreoglobulin antibodies is detected. The thyroid ultrasound verifies the right lobe of 46x14x15mm, the left lobe of 48x13x12mm, inhomogeneous and easily hypoechoic structure. The Edinburgh Postnatal Depression Scale indicates the presence of depression (total score 18). The patient is referred for a consultative examination by a psychiatrist and a nuclear medicine specialist. Psychiatrist indicates the introduction of Sertralin 50 mg tablets (1x1/2 for the first seven days, then 1x1) and Bromasepam tablets 1,5 mg (2x1/2), nuclear specialist Levotiroskin sodium tablets 50 mcg (1x1/2 for 5 days and 1x1 for 2 days). After six months, withdrawal of the symptoms of the disease and exclusion of therapy by a psychiatrist. Conclusion: Autoimmune thyroid disease is a significant and often unrecognized cause of postpartum depression. Early detection and timely therapeutic intervention of these have a significant role in the prevention and successful treatment of postpartum depression.