Background, Thrombosis is the most common complication of hemodialysis access, Few reports are available concerning the use of recombinant tissue plasminogen activator (rt-PA) to declot an arterio-venous (A-V) access, This report describes the use of rt-PA for this purpose in 17 A-V accesses, Methods, The rt-PA was infused manually using a small catheter directly into the A-V access in 10-mg doses at 1-2 hour intervals, to a maximum dose of 40 mg, The procedure was followed by angiography, through the same catheter, Results. One fistula could not be cannulated, and in three the lysis of the clot failed, The other 13 cases (3 fistulas, and 10 grafts 81%) had successful lysis with return of bruit and thrill, Most patients had dialysis the next day using the declotted A-V access, Angiogram detected stenosis in six patients and surgical revision was done 1-8 days after the treatment, In the other seven patients no organic lesions were found, and six of them have a functioning A-V access 50-395 days after the lysis, Only 10-20 mg of rt-PA was needed in 60% of the cases, No major complication occurred; minor local bleeding was noted in five patients (5/16, 31%), Conclusion, rt-PA can be considered safe, effective and fast for declotting thrombosed arteriovenous fistulas.