AIMS: 1) To assess positive CpIgG serology (CpIgG) prevalence in a cardiovascular risk population. 2) To evaluate its effects on endothelial production of PAI-1 as an expression of long term endothelial dysfunction/injury. STUDY POPULATION: 37 patients from a policlinic of cardiovascular risk were evaluated, 21 males, 16 females, 21 to 78 years (60.43 years +/- 12,4, SD), 16 DM, 24 hypertensive, 16 dyslipidemic patients and 7 smokers. METHODS: CpIgG (original validated test), PAI (ELISA Menarini). Statistical analysis: Mann-Whitney test. RESULTS: 1) CpIgG was positive in 24 patients (64.9%). 2) There were significant statistical differences (p<0.04) in PAI-1 level in patients with CpIgG positive and negative serology. CONCLUSIONS: 1) High positive CpIgG prevalence in no selected patients with cardiovascular risk factors. 2) This positive result was significantly related with high levels of PAI-1. 3) The elevation of PAI-1 suggests that Cp could also have effects in the middle-long term. 4) Moreover, it could participate in the high risk for thrombotic events.