A set of four commercially available multifilament glass-rovings with 320, 640, 1200, and 2400 tex embedded in concrete was investigated using pull-out tests and scanning electron microscopy. The increasing roving cross-section within this set arose from two geometrical factors, namely the number of filaments and the filament diameter. In general, pull-out loads and the pullout work increase with increasing roving cross-section, while the pull-out stress, the efficacy, and the roving penetration decrease. An attempt to separate the two geometrical factors revealed that an increase in the filament diameter reduced the mechanical performance of a roving to a much greater extent than an increase in the number of filaments. Consequently, effective textiles used for reinforced concrete should be made from a larger number of finer rovings such as the 640 tex rather than 2400 tex rovings.