Brief interventions (BI) are highly effective in reducing the health burden associated with alcohol, but to date, no study has evaluated their effectiveness in occupational health settings. EIST is a randomized controlled trial conducted among employees receiving occupational health care. Alcohol misuse was identified using the Waiting Room Audit. Inclusion was offered to employees with a score between 6 and 12 for women and 7 and 12 for men. After randomization, BI were conducted by occupational physicians (OPs). In the control group, the OHP’s assistant limited her role to handing out a booklet. Outcomes were assessed twelve months after enrollment. 33,488 employees were invited to complete the Audit. Alcohol misuse without dependence was identified in 7.1%. The analyzed sample included 787 individuals, of whom 435 were followed up at one year; in the control group, 44.8% had, according to the Audit, ceased misuse, and 51.6% in the IB group (p=0.15). In the IB group, there was a more marked reduction in Audit scores (p=0.0088) and consumption (p=0.038). Predictors of success in the IB group are: being younger, being female, not meeting DSM-IV criteria for dependence, and having received one or two informational booklets during the IB. The results suggest that IBs are effective in occupational health settings compared to written information, which itself influences substance use. Women and younger individuals respond better to IBs.