The aim of the work was to determine the effect of a high proportion of a novel modified starch preparation in the diet on selected nutrition parameters in rats, particularly it’s in vivo digestibility. The experiment was conducted on 20 males Wistar white rats, aged 9 weeks, fed 2 semi-purified experimental diets with a high (50%) addition of analyzed starch preparations: gelatinized potato starch preparation (Solamyl – S) and analyzed starch modified by high pressure homogenization of pastes (H). The intake of a diet, with a high addition of starch preparation H, had similar influence on growth and nutritional parameters in rats, including diet digestibility, as in case of feeding of diet with starch S participation. A high addition of new modified starch preparation H in the diet, in comparison with starch S, resulted in transit time acceleration and elevated water feces content, which can indicate an influence of bacterial degradation on digestibility results.