Current knowledge on PRRS virus immunology is still limited but it seems clear that modified live vaccines (MLV) are a reasonable choice for the immunisation of pigs (1). Cell-mediated responses after MLV vaccination could be responsible for limiting the duration of viraemia, and consequently the spread of the virus (2). Recently, interest in intradermal vaccination has increased due to research on the skin and subcutaneous tissues immunology. Although the intradermal PRRSV vaccination has been investigated (3), the high variability between different virus isolates makes it advisable to assess the intradermal response for each vaccine strain. The aim of this study was to compare the cell-mediated immune response developed in gilts vaccinated intramuscularly and intradermally with UNISTRAIN® PRRS.