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