Two field experiments were conducted during the winter seasons of 2013 and 2014, at the Experimental Station of the Faculty of Agriculture, Alexandria University, Alexandria, Egypt. Main aim was to study the effect of intercropping sugar beet with wheat, barley, and faba bean on the yield and some quality attributes of sugar beet and the used companion crops. In addition, to examine the effectiveness of intercropping using the new index – dry matter equivalent ratio (DMER) - in comparison to the traditional land equivalent ratio (LER) that was also investigated. The field trials were laid out in a split plot design with three replications. The three companion crop (wheat, barley, and faba bean) percentages (50, 75, and 100%) were tested in the main plots, while the sub plots were assigned to testing the variations among the seven intercropping patterns. Results revealed that the leaf area (m2), root yield (ton ha-1), harvest index and sugar yield (ton ha-1) of sugar beet were significantly affected by the interaction between the companion crop species and percentage in both seasons. Pure stands of sugar beet were superior in the four traits (leaf area, root yield, harvest index and sugar yield) followed by sugar beet intercropped with the lowest companion crops percentage. Intercropping with cereals (wheat and barley) resulted in slightly better values for these traits than intercropping with faba bean. Grain yields of wheat and barley and seed yield of faba bean reached the maximum in the pure stands and reduced by reducing the intercropping percentages of the three companion crops. On the contrary, number of pods and 100-seed weight of faba bean followed an opposite trend and reduced by increasing the intercropping percentages. Values of LER were greater than 1.00 in any intercropping system of sugar beet with wheat, barley, and faba bean, indicating an advantage of the intercropping patterns for land usage and yield gain. However, when determining the yield gain in terms of DMER, it was found that only in case of intercropping sugar beet with wheat there was a yield gain (DMER > 1). On the other hand, when intercropping sugar beet with barley and faba bean, there was loss in the overall produced yield (DMER < 1), indicating a severe competition between the sugar beet and the two companion crops. The DMER provided more realistic idea about the effect of intercropping, compared to the LER.