The aim of the study was to directly compare the potential of Montanide ISA720 and ISA206 oil-based adjuvant formulations on the induction of Th1/Th2-type of immune response, and to compare their effect to Complete Freund's adjuvant (CFA), a well known Th1 inducer. IgG isotype profiles (IgG1/IgG2a ratios) and specific cytokine secretion (IFN-gamma and IL-4) as specific markers of Th1/Th2-type of immune response were monitored in experimentally immunised mice using ovalbumin (OVA) as an antigen. Specifically, we wanted to evaluate whether the incorporation of immunostimulating peptidoglycan monomer (PGM) into two oil-based adjuvants (ISA720(PGM) and ISA206(PGM)) influences their capability on Th1/Th2-type of immune response switching. The experiments were carried out using two genetically different inbred strains of mice, i.e. CBA and NIH/OlaHsd mice, respectively. We found significant differences in immune responses related to the genetic background of the two mice strains used in the study. In both mice strains, ISA720 formulations had similar effect to the positive control, CFA, and induced the switch towards Th1-type of immune response specific for OVA. However, ISA206 formulations were less effective in inducing the switch towards Th1 in CBA mice, while in NIH/OlaHsd mice promoted the switch towards Th2-type of immune response.