Abnormal response to venous stasis is a frequent finding in patients with previous venous thrombosis. The factors studied to explain the response of the fibrinolytic system to venous occlusion (VO) have included tissue plasminogen activator (t-PA), PAI antigen and activity measurements as additional tests to the conventional euglobulin fibrinolytic activity. However, there is no consensus on the definition of an abnormal response. In order to further investigate the clinical relevance and the definition of good and bad responders (GR, BR), we have used a 10 min VO test in 109 patients with well documented venous thromboembolic events. Hematocrit, euglobulin clot lysis time (ECLT), diluted whole blood lysis time (DWBLT), tissue plasminogen activator (t-PA ag), fibrinolytic activity of euglobulins on fibrin plates (EFA), activity of the t-PA inhibitor (PAI act), a complete study of haemostasis, and a platelet count were performed before and after VO. Clinical characteristics did not reveal a significant difference between GR and BR. Among these 109 patients, 46 patients had a GR according to our previous definition (residual PAI≤2 U/ml). In this subgroup, results are homogeneous in the various fibrinolytic tests used. In the 63 remaining patients, results are heterogeneous: in 28 patients a BR was observed whatever the test used and could be attributed to a high basal PAI act in 17 cases, or a poor t-PA release in 11 cases. In the remaining 35 cases, interpretation of results is difficult: in 16 patients the anomaly of the t-PA-PAI balance coexists with a satisfactory response of global fibrinolytic activity judged on the ECLT after VO (≤90 min) or on the EFA after VO (t-PA>2 U/l). This discordance may be linked to a compensating activity of another pathway of the fibrinolytic system. In 19 cases the discordances remain unexplained. In these subgroups of BR, clinical characteristics were not clearly different. However, the subgroup ‘concordant BR’ seems to be more frequently associated with recurrences or familial thrombotic tendency. This work underlines the difficulties of clinical interpretation of hypofibrinolysis testing. Global tests (ECLT, DWBLT) and EFA are not only dependent on the t-PA-PAI balance but also on the contact phase and u-PA course. Combinations of tests and a better understanding of the multiple pathways involved will be necessary if we wish to prospectively identify patients at significant risk of thrombosis.