This thesis tests and compares the material toughness and material properties of 15-5PH stainless steel manufactured by direct metal laser sintering (DMLS) and conventionally using rolled steel. Effects from precipitation hardening heat treatment on the material toughness, material properties, and deformation were also analyzed. The test methods applied included Charpy impact testing, particle analysis, density measurement, specimen dimension measurements, fracture surface analysis, microstructure analysis, and elemental analysis. The results showed that DMLS has significantly lower material toughness and density than rolled steel. However density was concluded to not be a contributing factor of lower material toughness, but rather the nature of the DMLS process implementing a form of heat treatment. Precipitation hardening showed a decrease in material toughness in both methods of manufacturing, as a result of material hardening. Significant deformation by contraction was found in both forms of manufacturing as a result of precipitation hardening.