SUMMARYThe objective of the study was to determine a dynamic of nutrient accumulation in alfalfa leaves and stems. The experiment was conducted in two consecutive years (1999-2000) on three cultivars (Slavonka, Vuka and Os-88). Chemical analysis of leaves and stems were obtained from first and second growth. Samples were taken at four growth stages per growth. The results of the study indicate high statistical influence of growth stage (plant height), cut and investigated year on protein concentration and high statistical influence of growth stage on fiber concentration in alfalfa leaves. Protein and fiber content in stems were highly statistically influenced by year of investigation, cut and growth stage. Protein concentration in stems decreased by the plant height increasing but a greater decrease occurred in a first growth. Unlike proteins, the fiber content in stems increased by the plant height increasing but a greater increase occurred in a second growth. Cultivars did not significantly influence investigated traits..