Ultrasono-guided percutaneous catheter drainage of 28 abscesses and fluid collections was performed. In 24cases, operation was avoided and the patients were cured(24/28). Of these, 4 cases were recurred and repeatedcatheter drainage was performed. There were two failures and partial success was achieved in 2 cases; in thesepatients, operation was necessary, although the patients benefited from the percutaneous drainage. Cures andpartial successes totaled 26/28. We describe significance of the diagnostic needle aspiration, especially inpredicting the drainability of cavity contents. We review aspects of postprocedurecatheter management includingirrigation and timining of withdrawal.