We report the preparation of a low-temperature (—20°C), low-conversion (4.5%) emulsion polymer of 2-chlorobutadiene-1,3 which has been employed as a “linear” standard trans-1,4-polychloroprene. This “linear” standard was fractionated, and the fractions characterized by light scattering, viscometry, and gel permeation chromatography (GPC). The Mark-Houwink constants, K and a, were determined in tetrahydrofuran at 30°C and found to be 4.18 × 10−5dl/g and 0.83, respectively. Furthermore, polychloroprene was found to adhere to the concept of universal calibration. The GPC-intrinsic viscosity method for the determination of long-chain branching has been applied to polychloroprene polymers prepared at 40°C as a function of conversion. The degree of branching increases with conversion in a manner consistent with the accepted mechanism of free radical diene polymerization.