The aim of the current study was to check the safety of a vaccine (Porcilis(R) Glasser, Intervet Deutschland GmbH) in sows in their last third of pregnancy, and in suckling piglets. Up to now, the vaccine has only been approved for use in weaned piglets. Porcilis(R) Glasser is an inactived vaccine containing Haemophilus parasuis Serotype 5 as antigen. The trial was carried out in an infected herd in the north-west of Lower Saxony. A hundred and fifty-eight sows and their piglets (n= 1524) were included in the trial. The sows were randomly allocated to one of two treatment groups of equal size, and were injected at 6 and 2 weeks ante partum with either Porcilis(R) Glasser (vaccination group) or the Intervet adjuvant Diluvac(R) Forte (control group). Safety was evaluated by observing the sows for local and systemic reactions, though reproductive index, therapy and mortality were also recorded. The sows' progeny were also evenly divided into vaccination and control groups, and injected either with Porcilis(R) Glasser or Diluvac(R) Forte, in their 2nd and 4th week of life. In the case of the piglets, growth rates were also recorded as well as local and systematic reactions. In some sows (14 %), after the second injection, a small, local reaction was observed, and a minor increase in rectal temperature recorded. No influence was detected on the reproductive index. In the piglets, also, small local reactions and minor increases in rectal temperature were recorded following the second dose, while general condition and growth rates did not appear to be affected. The use of Porcilis(R) Glasser is therefore regarded as safe in pregnant sows and piglets.