Abstract: A blowout preventer ram assembly adapted to seal the mouth of the hole of oil and gas wells in the process of their drilling. The ram assembly incorporates two rams, each of which comprises a ram rubber constituted by two arcuate members of larger and smaller radii, and a ram block provided with a projection is placed in the gap therebetween. The ram rubber is reinforced on the end faces by control members each of which consists of two parts. The first part is defined by two rigidly interconnected plates arranged in the arcuate member of the ram rubber of a smaller radius. One face of each plate has a radius corresponding to that of the largest pipe of the set of pipes to be sealed, while a second face is arranged parallel to the end face of the ram rubber, and a third face is arranged at an angle to the first face and is in contact with the ram block.