Aim is to determine whether lactate clearance has value as mortality prognostic factor in shock patients, or not. A scrutiny, descriptive, prolective, homodemic, longitudinal study in patients older than 19 years, excluding chronic renal illness, hepatic insufficiency, neoplasias and diabetics on biguanides treatment, was performed. Arterial gasometry was used to obtain lactate rates at admission, 6, 12, and 24 hours as well as lactate’s clearance. Determinations between survivors and not survivors were compared, as well as correlation with APACHE II was performed. 41 patients were studied, 53.7% women and 46.3% men, mean age was 63.95 years. The diagnostics were septic shock in 29.2%, hypovolemic 63.4%, and cardiogenic 7.3%. The mortality in cardiogenic shock was 100%, with null lactate clearance. The survival rate was higher in hypovolemic shock as its lactate clearance rates (at 12 and 24 hours). Lactate clearance rates of less than 0 at 24 hours had a positive predictive value and a sensitivity of 80%. Lactate clearance at 6, 12, 24 hours among survivors and not survivors demonstrated statistical significance in the Univariate Analysis (p<0.002, p<0.000, p<0.000) respectively. The lactate clearance rate at 24 hours is a prognostic factor for mortality in patients in shock state.