OBJECTIVE: To correlate components of the plasminogen activator (PA) system with fertility outcome parameters in participants in an IVF/intracytoplasmic sperm injection (ICSI) procedure. DESIGN: Case-control study. SETTING: Outpatient clinic for IVF/ICSI treatment at the Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. PATIENT(S): One hundred and fifty-six couples undergoing an IVF/ICSI procedure. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), and t-PA-PAI-1 complex concentrations in the ejaculate, spermatozoa, and follicular fluid (FF). RESULT(S): Concentrations of t-PA were higher in spermatozoa of the male factor subfertility group (geometrical mean, 77.1 pg/million spermatozoa; 25th-75th percentiles, 31.8-211.2), compared to fertile men (geometrical mean, 1.91; 25th-75th percentiles, 0.74-5.79) and idiopathic subfertile men (geometrical mean, 3.14; 25th-75th percentiles, 0.97-9.97). Furthermore, the concentration of t-PA in spermatozoa was significantly associated with pregnancy (odds ratio [OR], 0.995). Likewise, a trend was shown for higher t-PA concentrations in the FF of women with fallopian-tube pathology (geometrical mean, 18.5 pg t-PA/mg protein; 25th-75th percentiles, 11.4-25.7) or endometriosis (geometrical mean, 18.8; 25th-75th percentiles, 11.4-27.1), compared to fertile women (geometrical mean, 14.3; 25th-75th percentiles, 10.3-17.6) and idiopathic subfertile women (geometrical mean, 13.9; 25th-75th percentiles, 9.5-17.8). Also, t-PA in FF is associated with the proportion of cleaved embryos (regression coefficient, 0.16). The concentrations of u-PA, PAI-1, and t-PA-PAI-1 complex were comparable between diagnostic subgroups in both men and women. CONCLUSION(S): The t-PA concentrations in spermatozoa and FF tend to be higher in human subfertility, and seem to be associated with some fertility outcome parameters.