Maraging steels are used in many tooling applications and for the production of high performance parts as they exhibit high strength and toughness due to a martensitic structure and the precipitation of intermetallic compounds. These steels are promising materials for additive manufacturing processes due to their low C content and fairly good weldability. In this work, a 1.2709 grade steel was fabricated by selective laser melting (SLM) and investigated with focus on evaluation of alloy properties as a function of thermal treatment, by microstructure analyses, tensile test, hardness measurement and differential scanning calorimetry. The results show that the as built samples feature full aging response, as confirmed by comparisons between as built and solution treated samples. Tensile strength after peak aging reached remarkably high values at the expenses of a significant drop in ductility whereas, in the as built samples a fairly high fracture elongation could be achieved.