The purpose of the study was to determine the influence of the Bioimmuno preparation administered in feed and/or immunisation with the Respisure One vaccine on the development of selected indices of non-specific and specific humoral immune response against Mycoplasma hyopneumoniae (Mhp) infections in pigs. The study was performed on 28 piglets at the age of 4 weeks, divided into four equal groups. The biopreparations were administered according to the following pattern: group I--Bioimmuno (IFI Olsztyn, Poland) with feedstuff at amount of 1 kg/50 kg of feed for 48 h before vaccination with Respisure One (Pfizer) on day 28 of life; group II--Bioimmuno only (1 kg/50 kg feedstuff) for 48 h before vaccination with Respisure One of groups I and III; group III--Respisure One only on day 28 of life (2 ml/animal i.m.) and group C (control)--PBS (2 ml/animal i.m.) simultaneously with vaccination of groups I and III. On days 0, 3, 7, 14 and 21 after immunomodulation and/or immunisation, the serum level of gamma-globulins, the activity of lysozyme (LSM) as well as the serum levels of cytokines: interferon gamma (IFNgamma), interleukin 1 beta (IL-1beta) and interleukin 6 (IL-6) were determined, as indices of non-specific immune response against Mhp infections in pigs. The study has revealed that in piglets after weaning the application of the Bioimmuno and/or Respisure One biopreparations improves the non-specific immunity parameters stimulating an increase in serum levels of gamma-globulins, lysozyme and cytokines (IFNgamma, IL-1beta, IL-6), while late appearing seroconversion confirms a minor role of specific humoral immunity in the protection against Mhp infection.