Objective of the study consisted in the evaluation of the effect of white mustard as a companion plant in the cultivation of broad bean, cultivar Bartek, on the level of plant infestation with black bean aphid Aphis fabae Scop., and also on the occurrence of its natural enemies. The field experiment comprised the following objects: control - broad bean, Bartek cv. as a homogenous crop, sown at 50 cm x 10 cm spacing; broad bean spaced 60 cm x 10 cm with white mustard as the crop intersown between the rows and broad bean spaced 50 cm x 10 cm, with a 50 cm wide mustard stripe surrounding the plot (in this case the width of broad bean stripes was 3 m). Broad bean cultivation in combination with intercropping white mustard, as well as in the form of surrounding sowing contributed to a significant decrease in black bean aphid abundance on the broad bean plants. The effect was visible mainly during the final period of the pest occurrence. The analysis of the occurrence of natural enemies of A. fabae demonstrated a strong relationship between the number of adult Coccinellidae with the number of aphid and their highest numbers in the homogenous broad bean cultivation. On the other hand, the predator to prey ratio in the case of larval stages of the major aphid predators, i.e. Syrphidae and Coccinellidae was more favorable in the presence of mustard as the companion plant.