Stainless steel 316L (SS 316L) powder was spheroidized by plasma processing to improve its suitability for powder 3D printing. The obtained spheroidized (sphero) powder was characterized in terms of its crystalline phases, elemental composition, morphology, particle size and distribution, light absorption, and flow properties. The elemental composition of the sphero powder met the Chinese standard for SS 316L except for its Si content. The volume fraction of ferrite increased after plasma processing. Furthermore, plasma processing was shown to not only reduce the mean size of the particles in the size range of 10 to 100 mu m but also generate particles in the size range of 0.1 to 10 mu m. The smaller particles filled the voids among larger particles, increasing the powder density. The light absorption was also increased owing to enhanced internal reflection. Although the basic flow energy decreased after plasma processing, the flow function (FF) value was smaller for the sphero powder, indicating a lower flowability of the sphero powder. However, the density of SS 316L pieces printed with commercial and sphero powders was 98.76 pct and 98.16 pct of the SS 316L bulk density, respectively, indicating the suitability of the sphero powder for 3D printing despite an FF below 10.