One widely used procedure -for immobilizing enzymes on nylon was first described by D.L. Morris,et. al.in 1975 (Biochem. J.,147, 153). This report describes the optimization of this procedure, leading to a reduction in reaction time from 20 hours to 80 minutes and concomitant increase in the activity of the open-tubular reactors by as much as a factor of four. Type 66 nylon reactors holding three different enzymes, glucose oxidase, catalase, and urease, were prepared by the modified procedure and tested in a segmented continuous flow instrument.