The pathogenesis of hypertension induced by recombinant human erythropoietin (rHuEPO) remains a subject of intense interest. The observation that patients treated with antiplatelet drugs never developed hypertension following rHuEPO therapy prompted us to study retrospectively the incidence and risk factors associated with the development of hypertension in 91 patients on renal replacement therapy who had commenced rHuEPO therapy in the last three years. Logistic regression analysis was used to determine the risk factors associated with the development or aggravation of hypertension during the first six months on rHuEPO therapy. The predictors were: age, gender, number of months on dialysis, antecedent of hypertension, use of antiplatelet drugs, and those parameters related with dose, route and magnitude of the hematological response to rHuEPO. Of the 91 patients studied, 34 developed hypertension (37%). Of the 34 patients who were on antiplatelet treatment, 2 (5.8%) developed hypertension, whereas among 57 who did not receive antiplatelet drugs, 32 (56%) developed it. By multiple logistic regression analysis, the best predictive variables over the development of hypertension were: age (odds ratio: 0.959, P = 0.02), antecedent of hypertension (odds ratio: 6.52, P = 0.002), and use of antiplatelet therapy (odds ratio: 0.030, P < 0.0001). The rest of the studied variables failed to explain the development of hypertension. Antiplatelet therapy may prevent the development of hypertension in patients treated with rHuEPO. Since the antiplatelet drugs used in this study did not have a significant hemodynamic effect, we infer that changes in platelet aggregability induced by rHuEPO may be involved in the pathogenesis of hypertension induced by this hormone.