The efect of aging processes on the tensile properties of C-18150 copper alloy samples, made by laser powder-bed-fusionadditive manufacturing (AM) process with three diferent fabrication orientations (horizontal, angled, and vertical to the builddirection), are investigated. For the as-fabricated C-18150 AM parts, horizontal and angled fabrication directions result inmarginally better tensile strengths and much improved strain-to-failure values than those of vertically built AM parts. Afterthe aging treatment, tensile strength can be signifcantly enhanced with a sacrifce of the strain-to-failure value. Moreover,the highest tensile strength is achieved by treating the as-fabricated samples at an aging temperature of 500 °C for 2 h. At800 °F (427 °C), both tensile strength and ductility are smaller than low temperature values (room temperature and 400 °F/204 °C). Phase constituents, microstructure, and composition distribution of the AM parts are characterized to gain insightinto the measured tensile properties.