This study was carried out in the Department of Anesthesia and Reanimation at AL-Assad University Hospital Lattakia Syria during the year 2012-2013 the study included 200 patients between 12 and 65 years old the most common surgical procedures they had were general surgery, urinary surgery, orthopedic surgery, genecology surgery. Patients were divided into two groups: for the first group: Propofol was used for induction and an inhaling gas with a suitable minimum alveolar concentration MAC was used for maintenance the gas used was Sevoflurane. For the second group: Thiopental or Propofol was used for induction and Sevoflurane for maintenance with MAC less than the suitable concentration. The aim of the study was to show the importance of Minimum Alveolar Concentration and keep a deep anesthesia in order to prevent awareness and recall. The result was better in the first group because the percentage of awareness and recall was less than in the second group. The study shows that the use of inhaling anesthesia is well, but the Minimum Alveolar Concentration MAC (Sevoflurane is the studied gas) must be controlled.