In the Federal Republic of Germany no large Q fever epidemics (more than 200 cases) have been encountered within the last 20 years; however, Q fever was prevalent throughout that period on a constant level (between 27 and 100 officially reported cases per year). Besides classical pneumonic Q fever, chronic forms associated with endocarditis, myocarditis and hepatitis were recently diagnosed for the first time in the Federal Republic of Germany. The disease Q fever in humans is often misdiagnosed as common cold or influenza, and more attention should be paid to this entity by the medical profession. Within ten years there has been a sharp increase of Q fever infections in livestock and pets as proved by seroepidemiologic investigations. Preliminary results of a seroepidemiological study indicate a parallel increase of seropositives in the human population, but further investigations on larger numbers of sera are required for statistic confirmation. There are reasons to believe that, in contrast to general opinion, in the Federal Republic of Germany C. burnetii is involved now in infertility in cattle, and besides being a zoonosis Q fever must be considered as a potentially important infectious disease of cattle causing economic losses in this country. Further investigations on this matter are required.