Method D Double cantilever beam (DCB) test is used for design/fitness-for-service material qualification and specification purposes. Material resistance to propagation of environmental cracks is expressed in terms of a critical stress intensity factor KISSC or K-limit values. Usually these values are used without considering the experimental uncertainties and material variability i.e. error estimation environmental conditions etc.However when comparing the sulfide stress corrosion cracking (SSC) performance of different materials the quantification of experimental uncertainties becomes of fundamental importance. To rank materials according to their fracture toughness attention should be paid to the error bracket associated with each value.In this work two methods for determining the uncertainties associated with NACE TM0177 Method D are presented. The first one consists in the estimation of the experimental uncertainties in measured parameters and the Monte Carlo method is used to obtain the uncertainty in Klimit. The second method treats the experimental data as sets that have an intrinsic variability (i.e.: variability of the medium material etc.) and the Monte Carlo method is used to obtain the uncertainty in Klimit.