The objective of this study is to determine the optimal dose of lidocaine-HCl for anesthetizing Siberian sturgeon, Acipenser baerii, investigate the relationship between anesthetic effectiveness and fish size, and to analyze re-anesthetic effects and stress responses to lidocaine-HCl use. The concentration of the anesthetic and fish body size significantly affected the anesthesia and recovery times. Anesthesia time was markedly decreased as both the lidocaine-HCl concentration and body size increased (P < 0.05), while recovery time decreased as the lidocaine-HCl concentration increased (P < 0.05). Anesthesia time and recovery time were decreased significantly as the lidocaine-HCl concentration and water temperature increased (P < 0.05). Plasma cortisol, plasma glucose, and lactic acid concentrations were indicative of stress reactions. At 1-, 2-, and 3-day intervals, the anesthesia and recovery times increased significantly as the number of anesthesia treatments increased (P < 0.05) but were not substbatilaly different between duplicate and triplicate treatments (P > 0.05). In 4-day interval groups, anesthesia and recovery times were hardly different (P > 0.05) among the initial, duplicate, and triplicate treatments. The second anesthesia treatment (P < 0.05) increased anesthesia and recovery times. As the number of anesthesia treatments increased (P < 0.05) anesthesia time decreased significantly, but recovery times hardly differed significantly with the increase in number of anesthesia treatments (P > 0.05). Lidocaine-HCl concentrations of 50 and 200 ppm in the larval and juvenile groups, respectively, showed an optimal anesthesia time of approximately 1 minute. The optimal anesthesia interval of lidocaine-HCl was 4 days, and frequent anesthesia resulted in negative effects by inhibiting sensitivity.