The intracoelomic implantation of satellite transmitters is associated with lower survival in surf scoters (Melanitta perspicillata) compared with other species of diving ducks, potentially due to physiologic alterations following physical exertion and stress caused by handling and confinement. The effect of intranasal administration of midazolam hydrochloride on survival of surf scoters surgically implanted with intracelomic transmitters was evaluated. Shortly after their capture in Forestville (QC, Canada) in the fall of 2013, 26 randomly selected adult female surf scoters were administered midazolam hydrochloride (4.6–5.9 mg/kg) intranasally. The same volume of saline (1 mL) was given to another 26 adult female surf scoters as a control group. All birds were surgically implanted with an intracoelomic transmitter equipped with a percutaneous antenna. Transmitters were programmed to transmit 2 hr each day for 30 days after implantation, and mortality was estimated for each group using the telemetry data. The association between the administration of midazolam and survival was assessed while controlling for other factors such as body mass, transmitter-mass-to-body-mass ratio, hematocrit, total solids, and duration of surgery, anesthesia, and confinement. The odds of presumed death in the saline group were 5.3 times higher than in the midazolam group (95% confidence interval: 1.7, 19.0; P = 0.004). The presumed mortality at 30 days for the midazolam group (23%) was lower than for the saline group (61%). No other variable was significantly associated with survival. These results suggest that sedation with midazolam shortly after capture increased the postsurgical survival of female surf scoters surgically implanted with intracoelomic transmitters.