Load separation constitutes the basis for the experimental evaluation of the J-integral by using the single-specimen technique. The objective of this present paper is to investigate the applicability of the load separation criterion for evaluating the ductile fracture mechanics parameters of acrylonitrile/butadiene/styrene (ABS) terpolymers. This criterion allows the load to be represented as the product of two separate functions, namely a material deformation function and a crack geometry function. Load separation implies a method for J-integral evaluation by using only a single load-displacement measurement. The original method for evaluating J used an energy-rate interpretation, which required several load-displacement measurements to be made for identical specimens with varying crack lengths. J methodology based on load separation introduces new parameters, i.e. eta, eta(el) and eta(pl), which greatly simplify the calculation of J and constitute the basis for the J-R multiple specimen technique. Recently, a method for both the experimental determination of the eta-factors and the verification of load separation, which is based on separation constants, has been proposed for the testing of steel. This method allows the calibration of the eta-factors in new test specimen geometries. This present paper attempts to evaluate experimentally whether the principle of load separation is valid when testing ABS polymers in a bending configuration in order to obtain a valid single J-testing method, and to calculate the eta plastic factor experimentally by using this new simple method based on the load separation criterion in non-growing-crack measurements. In addition, a new approach based on the load separation principle which allows not only the calculation of J from a single specimen, but also the calculation of J-R curves from one test measurement has recently appeared. This approach is called the ’normalization method’ and has already been applied to the J-testing of two rubber-toughened nylons and one ABS polymer. However, load separation has only demonstrated for different specimen geometries in steels. In addition, the load separation in ABS terpolymers has been verified in this present paper for growing cracks, by using an experimental procedure available in the literature.