A 22 year old man from Ethiopia suffered from progressive left inguinal pain and weight loss for ten months. The pain aggravated with leg movement, in particular with flexion of the left hip. ESR and CRP were slightly elevated, and a PPD was strongly positive. Abdominal ultrasound was normal but CT-scan revealed a left sided psoas abscess. Pott's disease was suspected and tuberculostatic therapy with INH, PZA, ETH, RIF was initiated immediately. A MRI of the spine excluded spondylodiscitis. Primary Tb psoas abscess was diagnosed. Treatment response after 5 weeks was clinically insufficient and CT-scan showed enlargement of the abscess. Treatment adherence was verified by drug prescriptions and INH urinary stix testing. M. tuberculosis, suspected microscopically in the puncture fluid, grew in culture and was fully drug sensitive. After 12 weeks, surgical abscess debridement had to be performed due to disease progression. The patient's health state improved considerably the first two postoperative months, inflammatory markers normalized, although a small residual abscess was still visible on CT. Subsequently, three months after surgery, pain reemerged, CT showed abscess progression. The patient had to be reoperated. Tb psoas abscess was a frequently described complication of Tb spondylodiscitis (Pott's disease) the first half of the last century and became rare thereafter in the Western hemisphere. However, the last two decades, due to migration policies and a worldwide increase of Tb epidemic because of socioeconomic destabilization and spread of the HIV-pandemic, Tb reemerged in Western countries. Therefore, physicians should be aware of atypical manifestations of tuberculosis. Primary Tb psoas abscess is extremely rare. Only four cases are described in the literature. In analogy to Pott's disease, therapy consists of tuberculostatic treatment, supported by surgical debridement.