This study's objective was to determine the effect of paramedic experience on orotracheal intubation success in prehospital adult nontraumatic cardiac arrest patients. This retrospective study analyzed all attempted intubations of prehospital adult nontraumatic cardiac arrest patients between January 1, 1997 and April 30, 1997 in an urban, all ALS service. Data were abstracted from EMS reports and intubation data forms. Variables included months of experience, number of patients in whom intubation was attempted, number of intubation attempts, success per attempt, and success per patient. Ninety-eight paramedics performed 909 intubations on 1066 cardiac arrest patients, yielding an intubation success rate of 85.3%. The median months of experience was 59.5 (Range 5-223). The median number of patients in whom intubation was attempted per paramedic was 10 (Range 1-36). The mean intubation success rate per paramedic was 80.6% (+/- 22.4, 95% CI 76.1, 85.1). There was significant correlation between total number of patients in whom intubation was attempted and intubation success rate (p <.001, R = 0.32). There was no correlation between months of experience and intubation success rate. In conclusion, the number of patients in whom intubation was attempted per paramedic was significantly correlated with the intubation success rate. Months of experience per paramedic had no significant correlation with intubation success rate.