The aim of the present study was to examine if different feeding frequencies have an influence on protein status and immune response in rats. Protein status of animals was characterised by [1-¹⁴C] leucine oxidation in postabsorptive phase and reflected by body growth rate and amount of titers in the serum after immunisation with thyreoglobuline. The feeding frequency tends to influence weight gain in groups fed with casein based diet: meals provided twice a day were more efficient. Breath test measurements showed no significant differences in ¹⁴CO₂ recovery for different meal frequencies but the tendency for higher values in groups fed with 6 meals was observed. The rodents fed with casein based diet showed larger amount of antibodies than soya based diet groups but it was significant only in the case of 2 meals. Increasing the feeding frequency from 2 to 6 meals significantly improved the immune response in soya protein fed groups. However there was no difference in body mass gain between these two groups. It could suggest that improvement of protein status resulted in better availability of amino acids for metabolism but the composition of these amino acids allowed only the increase of antibody production and not for productive purposes (growth). It might also suggest that at the marginal level of protein intake, the immune response (antibody production) was favourable for growth development when the meal frequency was increased.