Purpose: Catheter drainage of intra-abdominal abscesses has shown to be effective in reducing sepsis and mortality. We sought to determine whether or not tissue plasminogen activator (tPA), a fibrinolytic, is safe and facilitates resolution when used as an adjunct during drainage of intra-abdominal abscesses. Methods: A single-blinded, prospective, multi-center, randomized control trial was performed on patients presenting with image confirmed abscesses; the first group (n = 24) received catheter-directed tPA of their abscess and the second group (n = 23) had their abscess drained without tPA instillation. Variables examined included patient age, gender, location of the abscess, pre-drainage volumes and size of catheters inserted. Baseline variables were compared between tPA and non-tPA groups using a chi-square test for discrete variables and a Wilcoxon rank sum test for continuous variables and for the outcome of drainage volume. Results: Technical success of the drainage procedures was 100% for both groups. The tPA group had higher volume of drainage over the first three days (median for total after 3 days: without tPA: 300 mL vs. with tPA: 322 mL, p = 0.42). At days 4 to 7 the tPA group had significant greater drainage volume than did the non-tPA patient group, 150 mL vs. 110 mL (p = 0.046). The number of days to resume diet was also assessed in the 20 patients where this datum was available, 11 tPA and 9 non-tPA with no difference between groups. No adverse events, such as localized or systemic bleeding were encountered. Conclusion: Instillation of tPA into catheter directed intra-abdominal abscesses was safe, easy to perform and was associated with significantly improved drainage of abscesses from days 4 -7. S. A. Kotecha et al. 203