This study assesses the validity of daily self-reported drinking data obtained using an automated touch-tone interactive voice response (IVR) system.Subjects (N = 30) reported alcohol consumption daily for 28 days using the IVR system. Concurrently, breath and saliva samples were obtained each night for objective determination of blood alcohol concentrations (BACs). Partners living with the subjects provided collateral reports daily. Retrospective drinking records were obtained from both partners at the outset of the study and from the target subjects at the end of the study, using timeline follow-back procedures referencing the target subjects' drinking over the previous 28-day period.Subjects reported drinking on 55.2% of the 840 possible subject days, and positive BAC readings were obtained on 25.9% of these days. The overall correlation between self-report and measured BAC was .72. Within-subject correlations between daily IVR reports and measured BACs ranged from -.07 to .92, with a mean of .57. The correlations between self-reported drinking and the collateral reports ranged from .18 to 1.0, with a mean of .89. Correlations between the daily self-reports and the timeline follow-back records obtained at the end of the study ranged from -.22 to .96, with a mean of .51.IVR technology provides an innovative, user-friendly methodology for obtaining valid measures of daily alcohol consumption. The validity of these measures may be differentially highest for frequent, heavy drinkers, a group for whom traditional assessment methods often produce the most biased underestimates.