A 58-year-old man developed continuous fever of around 40 degrees C and a macular rash on the trunk and limbs one week after an eight-day visit to the island of Rhodos. Typhus was diagnosed on the basis of the clinical findings, the characteristic rash and a rise in antibody titre against Rickettsia prowazekii and mooseri (1:1280). The fever subsided and the patient's general state markedly improved within three days of starting antibiotic treatment with doxycycline. Five days after hospital admission renal function deteriorated, serum creatinine rising from 1.7 to maximally 8.7 mg/dl. Renal biopsy on the eighth day of illness revealed, in concordance with the diagnosis of a rickettsial infection, acute granulomatous interstitial nephritis. Doxycycline administration was continued for a total of 18 days and renal function improved. Two weeks after discharge serum creatinine had fallen to 1.8 mg/dl and to 1.2 mg/dl after 6 months. The antibody titre against Rickettsia prowazekii had fallen to 1:20 about 12 weeks after discharge. Early antibiotic treatment of typhus is of importance to avoid irreversible renal damage.