Esophageal candidiasis is the most common infectious disease of the esophagus. The diagnosis is based on gastroscopy, and in many cases, biopsy samples should be taken as well. If we do not know of any risk factors for an immunocompromised condition, it is a mutual responsibility to confirm or exclude any potential chronic disease in the background, thus not just the secondary complication but also the primary disease could be treated. Without this knowledge, in many cases, the correct diagnosis may be delayed for months or even years, which may risk the successful treatment. We present the case of a 58-year-old healthy woman without any chronic disease, who was referred to our clinic with dysphagia. Due to her complaints we performed a gastroscopy, upon which advanced esophageal candidiasis was diagnosed, hence she was started on oral systemic antifungal treatment. Although we could not explore any risk factors, further investigations behind the immunocompromised condition revealed a positive immunoserology test for HIV. The take-home message of our case is that in the case of esophageal candidiasis, the cause of immunosuppression must be searched for, of which HIV serology is crucial. Thanks to the prompt and correct diagnosis, we could start the suitable treatment of the underlying disease. Orv Hetil. 2023; 164(22): 878-880.