It has been proved in many studies that Lactate and Lactate dehydrogenase (LDH) are associated with mortality. In this study lactate test values of inpatients were analyzed with Support Vector Machines (SVM) to identify patients in high risk of death. In the data set containing 686 records with lactate results; 219 patients treated in the pediatric service and 467 of the patients are adults. Lactate levels of 331 patients are normal and levels of 355 patients are high. 89 patients with high lactate levels were recorded as dead. 97%, 96.6% and 92.3% accurate mortality classification rates were recorded with analyzes performed using different data sets and variables. Patient's risk assessment can be assessed with such findings and treatments can be planned. Prediction of patients under high risk can provide opportunities for early intervention and mortality levels can be red.