Purpose: This study was conducted to determine the hemodynamic and ventilatory changes during implant surgery with intravenous conscious sedation, and whether preoperative anxiety, gender or age influence these parameters. Patients and Methods: A prospective study carried out between May 2004 and February 2007, on 102 patients treated with dental implants under local anesthesia and conscious intravenous sedation. Patients completed a questionnaire prior to surgery to evaluate preoperative dental anxiety using Corah's scale. The hemodynamic and ventilatory changes were evaluated by monitoring systolic pressure (SP), diastolic pressure (DP), heart rate (HR) and oxygen saturation (SaO2). These values were collected at 5 points during surgery; before commencing the operation (baseline value), during local anesthetic injection, at the moment of incision and raising of a mucoperiosteal flap, during implant placement, and finally at suturing. Intravenous conscious sedation was administered between baseline value and injection of the local anesthetic. Results: The highest SP and DP were recorded at baseline and at suturing. The highest HR was recorded at the moment of incision and raising of the mucoperiosteal flap; the lowest SaO2 was recorded at local anesthetic injection. There was no relationship between hemodynamic and ventilatory values and preoperative anxiety or gender. A greater age was associated with higher SP and lower SaO2, these differences being statistically significant. Conclusions: Most of the cardiovascular and ventilatory changes induced by the implant surgery with intravenous conscious sedation were within normal ranges. The results indicate that midazolam with fentanyl do not produce important hemodynamic and ventilatory changes, being a good association for intravenous conscious sedation in dental implant surgery. © Medicina Oral S. L.