To determine whether the success rate for endotracheal intubation improves after implementing the use of neuromuscular blocking (NMB) agents in an air medical program, this retrospective study analyzed all patients requiring endotracheal intubation at two air medical programs (nurse/paramedic crews) over a 5-year period. Air medical program A, the control group, had employed NMB agents throughout the entire study period. Air medical program B, which did not use NMB agents from July 1, 1989 through June 30, 1992, implemented their use starting July 1, 1992. For program A, the overall intubation success rate was 93.5% (202 successful intubations in 216 patients) and the successful intubations/total attempts ratio was 0.67 (202 of 301). For program B, the overall intubation success rate improved from 66.7% (46 successful intubations in 69 patients) before NMB agent use to 90.5% (57 in 63) after NMB agent use (P = .001). The successful intubations/total attempts ratio increased from 0.36 (51 of 141) prior to NMB agent use to 0.48 (63 of 132) after NMB agent use (P = NS). In comparing the 92 patients who did not receive NMB agents to the 40 patients who did, the intubation success rate increased from 69.6% (64 of 92) to 97.5% (39 of 40) (P < .001) and the successful intubation/total attempts ratio increased from 0.36 (73 of 202) to 0.58 (41 of 71) (P = .007). With the use of NMB agents, program B's overall intubation success rate increased significantly, matching the results of program A.