An experimental and analytical study of square three-point bend specimens was conducted to investigate the elastic-plastic fracture toughness of a high-strength low-strain hardening steel using shallow and deep crack test specimens.Changes in CTOD level with varying crack depth to width rati's of CTOD specimens were investigated for this material and compared to other results to determine how material properties, such as the strength level and strain hardening, affect the CTOD level for varying a/W ratios.