Our purpose was to obtain epidemiological measures of the association between habitual alcohol consumption, alcohol consumption before the event and alcohol abuse/dependence, and emergency room (ER) attendance compared to the general population in Pachuca-Hidalgo, a city located in the central area of Mexico. The study was a population based case-control design. Data consisted of breath samples to estimated blood alcohol concentration, as well as an interviewer-administered questionnaire, collected on a 24-hr basis, during the entire week, in each of the three main ERs of Pachuca. Cases were all patients who visited the three main hospitals ERs during the study period, classified according to their status as an injured or noninjured (medically ill) patient (n = 1511). The general population sample (n = 920) serves as a comparison group for both types of patients. Injured patients in the ER sample were significantly more likely to report high frequency/high quantity of drinking during the last 12 months than the general population [odds ratio and 95% confidence intervals = 5.55 (1.72-17.97)] and to report drinking within 6 hr before the injury. These relationships did not hold for noninjured patients. Both types of patients were more likely to report high frequency of drunkenness during the preceding 12 months, to be positive for alcohol dependence and to report drug use. We found in the city of Pachuca, a large relationship between habitual alcohol consumption and ER injuries. These findings support associations of alcohol consumption and admission to an emergency room found in ER and general population studies in other countries. Due to the increases in the risk found for abuse/dependent in both injured and noninjured patients, they both would benefit with a brief intervention strategy for reducing their alcohol consumption.