Purpose of investigation. To evaluate whether lymphvascular space involvement (LVSI) is a risk factor for relapse of disease and lymph node metastasis in endometrial cancer. Methods. From 1978 till 2003, 609 patients with epithelial endometrial cancer were treated at the Groningen University Medical Center. The association of LVSI and relapse of disease was evaluated in the total group of 609 patients and in a ‘ low’ and ‘ high’ risk stage I endometrial cancer group. In 239 surgically staged patients, the relation of LVSI and lymph node metastasis was investigated. Results. The median age at diagnosis was 63 years (range 27- 92 years) with a median follow- up of 58 months (range 0- 236 months). More than half of the patients (56% ) received adjuvant radiotherapy. LVSI was present in 123 patients (25,6% ), and a prognostic factor for relapse of disease (multivariate analysis, P < 0.0001). In the ‘ low’ and ‘ high’ risk stage I endometrial cancer patients an increase of 2.6 times in relapse of disease was observed in the presence of LVSI. LVSI positive tumors were more likely to have metastasized to the pelvic lymph nodes (multivariate analysis, P = 0.001). In patients with proven negative nodes, LVSI was a prognostic factor for relapse of disease (univariate analysis, P = 0.02). Conclusion. LVSI is a predictor of nodal disease and an independent prognostic factor for relapse of disease in all stages of endometrial cancer. Patients with stage I endometrial cancer with positive LVSI are at risk for relapse of disease and might therefore benefit from adjuvant therapy. Content. The presence of lymphvascular space involvement (LVSI) in endometrial cancer is significantly and independently associated with an increased risk of pelvic lymph node metastases and/or relapse of disease. To investigate whether lymphvascular space involvement (LVSI) is a risk factor for relapse of disease and lymph node metastasis in endometrial cancer. Methods. From 1978 till 2003, 609 patients with epithelial endometrial cancer were treated at the Groningen University Medical Center . The association of LVSI and relapse of disease was evaluated in the total group of 609 patients and in a ’low’ and ’high’ risk stage I endometrial cancer group. In 239 surgically staged patients, the relation of LVSI and lymph node metastasis was investigated. Results. The median age at diagnosis was 63 years (range 27-92 years) with a median follow-up of 58 months (range 0- 236 months). More than half of the patients (56%) received adjuvant radiotherapy. LVSI was present in 123 patients (25,6%), and a prognostic factor for relapse of disease (multivariate analysis, P <0.0001). In the ’low’ and ’high’ risk stage I endometrial cancer patients an increase of 2.6 times in relapse of disease was observed in the presence of LVSI. LVSI positive apositers were more likely to have metastasized to the pelvic lymph nodes (multivariate analysis, P = 0.001). In patients with proven negative nodes, LVSI was a prognostic factor for relapse of disease (univariate analysis, P = 0.02). Conclusion. LVSI is a predictor of nodal disease and an independent prognostic factor for relapse of disease in all stages of endometrial cancer. Patients with stage I endometrial cancer with positive LVSI are at risk for relapse of disease and might therefore benefit from adjuvant therapy. Content. The presence of lymphvascular space involvement (LVSI) in endometrial cancer is significantly and independently associated with an increased risk of pelvic lymph node metastases and / or relapse of disease.