Objectives. We examined whether alcohol advertising on cable television is associated with adolescent viewership. Methods. Using Nielsen data for every national cable alcohol advertisement from 2001 to 2006 (608 591 ads), we examined whether ad incidence in a given advertising time slot was associated with adolescent viewership (i.e., the percentage of the audience that was aged 12–20 years) after we controlled for other demographic variables. Results. Almost all alcohol ads appeared in time slots with audiences made up of 30% or fewer underage viewers. In these time slots (standardized by duration and number of viewers), each 1-percentage-point increase in adolescent viewership was associated with more beer (7%), spirits (15%), and alcopop (or low-alcohol refresher; 22%) ads, but fewer wine (−8%) ads (P < .001 for all). For spirits and alcopops, associations were stronger among adolescent girls than among adolescent boys (P < .001 for each). Conclusions. Ad placements for beer, spirits, and alcopops increased as adolescent viewership rose from 0% to 30%, especially for female viewers. Alcohol advertising practices should be modified to limit exposure of underage viewers.