A 31-year-old woman was admitted to the local department of endocrinology for control of known anti-TPOpositive hypothyroidism during pregnancy. The clinician noticed a remarkable hyperpigmentation. Primaryadrenal insufficiency was diagnosed and treatment with cortico- and mineralosteroids commenced. Diagnosis ofprimary adrenal insufficiency during pregnancy is challenging as many symptoms overlap with normalsymptoms of pregnancy. The usual diagnostic criteria cannot be used due to the altered hormone concentrationsduring pregnancy.