The influence of humic acids on Pisum sativum L. seed swelling process was studied. Humic acids (HA) were applied during seed swelling by watering the seeds for one hour in the first, fourth and eight hour of the process. Three different concentrations of HA 0.005 [gC dm⁻³]; 0.01 [gC dm⁻³]; 0.02 [gC dm⁻³] in buffer phosphate solution at pH=6.5 were used. The control sample was the pea seeds watered in buffer phosphate solution at pH=6.5 without humic acids. All of the pea seeds were placed on Petri dishes onto full water capacity filter paper. Humic acids at concentration 0.02 [gC dm⁻³] increased the fresh mass of swelling seeds when applied in the first hour of experiment. It was also noted that all concentrations of humic acids applied in the first hour of experiment increased the percentage of pea seeds with visible radicle at the end of experiment.