In this article, an affordable split-and-recombine polymer static micromixer and its fabrication process are described. The structure of the micromixer was designed to take advantage of the process capabilities of both ultraprecision micromachining and microinjection molding. This arrangement allows a considerably short machining time, high productivity, and flexibility as compared with many of the previous fabrication processes used in manufacturing of micromixers, for example, the cleanroom process. Moreover, in recent years, microinjection molding has become a cost effective mass production method for polymeric components with micro and nano scale features. Specifically, in this study four dominating processing parameters in microinjection molding, including melt temperature, injection velocity, packing pressure, and packing time were selected as variables to investigate their effects on replication quality. Both experimental and numerical results showed that the packing pressure and packing time played an important role on replication, followed by melt temperature while the injection velocity seemed to have no influence on replication. Finally, experiments using two colored water solutions were conducted to evaluate the device performance, and the mixing result demonstrated the successful fabrication and performance of the injection molded polymer micromixer. POLYM. ENG. SCI., 50:1594-1604, 2010. (C) 2010 Society of Plastics Engineers