A quasi-experimental trial, yielding 30 data points per system, was earned out to investigate the influence of component parts on the overall performance of urinary sheath systems Information was obtained on the effect of changing both the sheath and leg-bag Data from the trial was supported by accurate stocktaking analysis over two periods of 4 weeks’ duration when alternative systems were used in a clinical setting Results suggest that leg-bag design profoundly influences the performance of urinary sheaths A significant difference in the performance of two urinary sheaths in the presence of the same leg-bag was also observed The significance of the findings for nursing practice is discussed since the optimum performance, from the components tested, was a‘hybrid'system A continuing line of investigation is suggested whereby improvements in the composition of urinary sheath systems could be made from nursing research