The presence of H2S in well fluids imposes severe restrictions on the use of tubular goods because of sulfide stress cracking (SSC). Increasing developments of deep sour wells require high strength OCTG with improved SSC resistance. The appropriate selection of materials for well completion is an important factor in economic success of oil and gas production. Corrosion cracking behaviour of metals for the range of environments expected in service is the main criterion. Such knowledge is gained partly from service experience, but mainly from appropriate laboratory testing at the design stage. The Double Cantilever Beam test has elicited considerable interest despite of the traditiorxd lab testing procedures as NACE tensile, Bent beam and C-ring tests. This popularity is attributed to the quantitative characterization nature of the test... Keywords : Oil Country Tubular Goods, Carbon Steels, High Strength, Sulfide Stress Cracking, DCB Test, Fracture Mechanics, Sour Environment, Hydrogen Sulphide, Casing, C90, C95, C 100, C110