Although alcohol use and hard drug history were found to predict aggressive behavior, marijuana use did not, when controlling for gender and age. Competing explanations regarding distinctive aggressive personality traits were ruled out. Although sample characteristics limit the generalization of these findings, the results suggest that marijuana use is either not associated or indirectly associated with self-reported aggression among frequent, long-time marijuana users. These data and conclusions are consistent with the majority of research that has shown no relationship between marijuana use and aggression. In an effort to target frequent marijuana users, three organizations committed to altering drug laws were asked to use their mailing lists in order to solicit participation in a survey in return for a chance to win a cash prize. A total of 9,810 individuals completed the Internet survey; however, only those participants who reported both smoking marijuana and drinking alcohol in the previous 30 days were included in the study (n=6,910). Participants had been smoking marijuana an average of 14.24 years. On each occasion of alcohol drinking, participants reported consuming a mean of 4.55 drinks. Fifty-six percent reported using cocaine; 13 percent had used crack; 29 percent had used methamphetamine; 40 percent had used speed; and 8 percent had used heroin. The aggressive acts that were the main dependent variable of interest were slapping, kicking, pushing, insulting, pulling hair, twisting an arm, throwing things, yelling, breaking things, arguing, fighting, and threatening someone. Structural equation modeling was used in conducting the analysis. 3 figures and 43 references