In Poznań and Leszno districts, serological survey of Q fever among cattle and sheep have been performed since 1973. Coxiella burnetii infections have not been detected until 1985. During this period 28,272 blood samples derived from cattle and sheep have been tested. For the first time in Poznań district, seropositive cattle were found in 1986 (5.5%). In the next year percentage increased to 16.3% and in following years has been on similar level. In Leszno district, serum antibodies to C. burnetii were detected in cattle in 1988 (25.9% seropositives). On the consecutive years, percentage of seropositive animals has decreased and in 1991 was 3.2% only. During these years there were 2.3 and 8.3% seropositive sheep detected in Poznań and Leszno districts respectively. Serological survey of C. burnetii infection has been performed among people exposed to this agent occupationally who undergo intermittent obligatory testing for brucellosis. In Leszno district among 4214 persons tested, 34.4% were seropositive. In Poznań district from 1988 to 1991 antibodies to C. burnetii have been detected in 22.7% of 6396 people tested. From year to year the percentage of seropositives fluctuated from 16.6 to 34.7%.