An effective and novel technique for improving the biocompatibility of a biograde 316 LS stainless steel through the application of CO2 laser treatment to modify the surface properties of the material is described herein. Different surface properties, such as surface roughness, surface oxygen content, and surface energy for CO2 laser‐treated 316 LS stainless steel, untreated, and mechanically roughened samples were analyzed, and their effects on the wettability characteristics of the material were studied. It was found that modification of the wettability characteristics of the 316 LS stainless steel following CO2 laser treatment was achieved. This improvement was identified as being mainly due to the change in the polar component of the surface energy. One‐day cell adhesion tests showed that cells not only adhered and spread better, but also grew faster on the CO2 laser‐treated sample than on either the untreated or mechanically roughened sample. Further, compared with the untreated sample, MTT cell proliferation analysis revealed that the mechanically roughed surface resulted in a slight enhancement, and CO2 laser treatment brought about a significant increase in cell proliferation. An increase in the wettability of the 316 LS stainless steel was observed to positively correlate with the cell proliferation. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 73B: 148–156, 2005