To determine the frequency of drunk driving in professional drivers (Via Blanca, Havana City), we carried out a descriptive study of 832 drivers selected by multistage stratified sampling. A structured interview with each driver was carried out to record the variables under study, and a breath alcohol test was subsequently performed. The frequency of drunk driving was 8.18% (95% CI, 5.94%-10.42%), with a predominance of drivers with alcohol levels<or=0.24% (51.07%). Drunk driving was more frequent in "high risk" hours, in drivers aged between 40 and 49 years old (10.3%), and in those with 15 to 24 years of experience (11.02%). The frequency of drunk driving found in this study highlights the need to design traffic accident prevention strategies.