【Abstract】 Objective This single-center, open-label control clinical study was performed to test the effect of a dose (20000 IU/mL) urokinase 24 hours dwelling-lock thrombolysis technique to clear double lumen central venous catheters for dialysis and reestablish patency when occluded by thrombus. Safeties and efficacies of the new technique were compared with those of regimen recommended by K/DOQI guideline. Methods Adult dialysis patients with nontunneled double lumen central venous catheters occlusion were treated with 20000 IU/mL intracatheter urokinase 24 hours dwelling-lock thrombolysis technique(treatment group) or 5000 IU/mL urokinase instillations thrombolysis regimen recommended by K/DOQI guideline(control group). Lumen patency, side effects and cathether thrombus reoccurrence were assessed and compared between the two groups after the treatment. Results A total of 88 cases of non-tunneled double lumen central venous catheters occlusion were enrolled in the study during Aug 2003 and Dec 2008. 45 were in treatment group and 43 in control group. Overall, 20000 IU/mL urokinase 24 hours dwelling-lock thrombolysis technique successfully restored total catheter patency (all treated lumens) to 88.2% of catheter ocllusions (45 of 51). Patency was restored in 90.2% of devices (46 of 51) in 5000 IU/mL urokinase instillations group. Patency was restored equally in both group and no side effects were recorded in both treatments. Catheter occlusions reoccurrences were also equal in both groups. Conclusion The use of a new 20000 IU/mL intracatheter urokinase 24 hours dwelling-lock thrombolysis technique is simple, safe and effective for the restoration of patency to occluded dialysis nontunneled double lumen central venous catheters.