Chronic periodontitis is one of the most common disease in clinical dentistry, which needs various surgical interventions to treat the moderate to severe destruction of supporting periodontium. Most patients have fear and anxiety to these surgical procedures and some dentists also have problems to deal with these patients. Applying the conscious sedation technique in outpatient units, periodontists have become to manage their patients successfully without any fear and anxiety and increased the level of patients' satisfaction. Particularly, periodontal treatments require relative long chair-time and patients are usually reluctant to the periodontal instruments used in the oral cavity. This study is focused on the sedation procedure with intravenous midazolam infusioon performed in Department of Periodontology, Ewha Womans University Hospital. The whole procedure of intravenous midazolam sedation is briefly reviewed from patient selection to patient discharge.