This study contributes to new literature on patterns of conjoint alcohol and marijuana use within a college population. In addition to examining patterns of use in college and subsequent consequences, this paper will also help identify substance-specific consequences. Participants included 473 entering freshmen at a Bay Area university who reported prior initiation of alcohol and/or marijuana and who completed a survey during their first academic quarter. Data for this study was collected during the spring follow-up time point of the larger study. Participants were asked to complete brief questionnaires regarding demographics, alcohol and marijuana use over the previous months, alcohol-related consequences and marijuana-related consequences. A primary objective of this study was to determine whether there are differences in demographics, use and consequences as a function of alcohol-marijuana use. As such, three groups were created: 1) conjoint users, 2) SAM users, and 3) alcohol-only. Overall alcohol use was operationalized using a modified quantity frequency index (QFI: Callahan & Cisin, 1968). Chi-square tests were used to identify demographic risk factors by group and a one-way ANCOVA was used to evaluate group-wise differences in total number of alcohol-related problems by class membership. A one-way MANCOVA was used to examine differences on domains of more severe problems (i.e., sexual and legal), and differences in alcohol-related blackouts and DUIs were examined using chi-square tests. Results indicate that males are more at risk of becoming conjoint alcohol-marijuana users and SAM users compared to the alcohol-only category. Furthermore, significant differences were indicated in total number of alcohol-related problems by class membership. When evaluating group-wise differences in specific alcohol-related problems as well as specific marijuana-related consequences by class membership, it was found that blackout risk was significantly different between all groups, as well as DUI incidents and academic problems. This data suggests that conjoint use of alcohol and marijuana, whether sequential or SAM, is associated with more negative consequences relative to students who limit their substance use to alcohol. Overall, findings provide a clear empirical basis for measuring conjoint use with more sophisticated measures that disentangle event-level timings of each substance's use, as SAM use appears to have more deleterious effects than conjoint use patterns that do not produce interacting pharmacological effects.