An experiment was conducted to investigate into the effects of Ecklonia maxima extract (Kelpak SL) on yield, protein and ash contents of two bean cultivars. The study was carried out in 2012 - 2014 in Poland. During the growing season, 0.2% and 0.4% solutions of the bio-stimulant were applied by single and double spraying of plants against a control. The highest number and weight of grains were found when the plants of ‘Toska’ cultivar were single sprayed with 0.2% seaweed extract. Double spraying the plants with the 0.4% solution of Kelpak SL increased the number, its weight and the number of pods in cultivar ‘Aura’. The application of Kelpak SL increased protein content of grains in both bean cultivars. Higher the dose the double foliar application of the bio-stimulant, more was the ash content of the grain of plants of ‘Toska’ cultivar.