Available short-acting intrathecal anesthetic agents (chloroprocaine and prilocaine) offer an alternative to general anesthesia for short-duration surgical procedures, especially ambulatory surgeries. Factors determining the choice of anesthesia for short-duration procedures have not been previously identified. Methods: This observational, prospective, multicenter, cohort study was conducted between July 2015 and July 2016, in 33 private or public hospitals performing ambulatory surgery. The primary objective was to determine the factors influencing the choice of anesthetic technique (spinal or general anesthesia). Secondary outcomes included efficacy of the anesthesia, time to hospital discharge, and patient satisfaction. Results: Among 592 patients enrolled, 309 received spinal anesthesia and 283 underwent general anesthesia. In both study arms, the most frequently performed surgical procedures were orthopedic and urologic (43.3% and 30.7%, respectively); 66.1% of patients were free to choose their type of anesthesia, 21.8% chose one of the techniques because they were afraid of the other, 16.8% based their choice on the expected ease of recovery, 19.2% considered their degree of anxiety/stress, and 16.9% chose the technique on the basis of its efficacy. The median times to micturition and to unassisted ambulation were significantly shorter in the general anesthesia arm compared with the spinal anesthesia arm (225.5 [98; 560] min vs. 259.0 [109; 789] min; p = 0.0011 and 215.0 [30; 545] min vs. 240.0 [40; 1420]; p = 0.0115, respectively). The median time to hospital discharge was equivalent in both study arms. In the spinal anesthesia arm, patients who received chloroprocaine and prilocaine recovered faster than patients who received bupivacaine. The time to ambulation and the time to hospital discharge were shorter (p < 0.001). The overall success rate of spinal anesthesia was 91.6%, and no significant difference was observed between chloroprocaine, prilocaine, and bupivacaine. The patients' global satisfaction with anesthesia and surgery was over 90% in both study arms. Conclusions: Patient's choice, patient fear of the alternative technique, patient stress/anxiety, the expected ease of recovery, and the efficacy of the technique were identified as the main factors influencing patient choice of short-acting local anesthesia or general anesthesia. Spinal anesthesia with short-acting local anesthetics was preferred to general anesthesia in ambulatory surgeries and was associated with a high degree of patient satisfaction.