Acrylonitrile–butadiene–styrene (ABS) is a popular engineering thermoplastic and it is the most common material used in fused deposition modeling (FDM) technology. This technology is nowadays used for the production of prototypes and functional parts as well. It is therefore critical to know the mechanical properties of these parts, which, is as expected different from their nominal values.In this work the tensile strength of parts build with the FDM process is measured. ABS and ABS plus parts were built with different building parameters and were tested according to the ASTM D638-02a standard on a Schenk Trebel Co. tensile test machine. It was found that the building direction does not significantly influence the tensile strength of the parts, although the parts were anisotropic, as expected. Parts build with larger layer thickness showed lower tensile strength. The average deviation between nominal and experimental tensile strength was about 15% for the ABS and about 42% for the ABS plus material. The ABS plus showed on average 9% higher strength than ABS.Copyright © 2014 by ASME