Vaccination against porcine parvovirus (PPV) infection were carried out in the breeding herd were reproductive failure and significant number of small litters occurred. Antigen of PPV was demonstred in the lungs from dead fetuses. It was found that 96% of 50 sows sera and 55% of 40 gilts sera have antibodies to PPV. For evaluation of the efficacy of the vaccine five hundred thirthy eight sows and 355 gilts were vaccinated once — 6 weeks before mating with Nobi — Porvac Parvo vaccine. Efficacy of vaccination was evaluated on the basis of reproductive performance of vaccinated and non vaccinated gilts and sows. The average litter size of immunized gilts was 0,68 piglet larger than non-vaccinated. The percentage of small litters (< 6 piglets born) was lower among the vaccinated gilts (4,22%) in comparison with untreated control (14,42%). The reproductive performance of vaccinated sows was not improved in comparison with unimmunized. The results have indicated that even in endemically PPV — infected herds a significant percentage of gilts is seronegative at the time of breeding and therefore the vaccination of gilts is recommended. Vaccination of sows in this herd seems not to be necessary. Serological investigation carried out in quinea pigs revealed good immunogenic properties of the vaccine. It was also confirmed that the vaccine is safe for foetuses.