One of the goals of hemodialysis is to maintain normal hydration status in ESRD patients. Pre hemodialysis systolic blood pressure is usually used as a clinical parameter of hydration status and to set ultrafiltration rate before Hd. It is unclear how much pre-Hd SBP correlated with hydration status. The aim was to determine correlation between pre-Hd SBP and hydration status before Hd. An observational correlation study was performed in two dialysis centers in Santiago, Chile, from January-June, 2011. Adult patients in Hd for at least three months, who gave their informed consent were included. Patients with pacemaker, amputee, hospitalized and metallic prostheses were excluded. Total-body water and overhydrated were assessed with bioimpedance spectroscopy before the first and third dialysis session of the week. Pre-Hd SBP, pre-Hd body weight, pre-Hd TBW and pre-Hd OH, were analyzed using Pearson correlation and linear regression model. 96 measurements were assessed, 52 % were male with median age 59.5 years. The correlation between pre-Hd SBP and pre-Hd overhydration was r=0.33, and total body water r=0.15, with a predicted value, R2=0.10 and R2 =0.14 respectively. Pre-Hd SBP had low correlation with pre-Hd hydration status and by itself, is not a reliable parameter to set ultrafiltration rate before Hd. Nevertheless Pre-Hd body weight predicted in 70 % the pre-Hd TBW.