Disclosed is a signed multiplier for use in a data processing system that handles 2's complement operands. The signed multiplier operates to form a preliminary product independently of the signs of the multiplier and multiplicand. While the multiplication is in progress, the signs of the multiplier and multiplicand are checked. For multiplications where either one of the operands (multiplier or multiplicand) is negative, the preliminary product is modified by one or two correction factors. The correction factors are multiples of the 2's complements of the operands. The correction factor or factors are added to the preliminary product to form the final product.