In State v. Sisco and State v. Cheatham, the two divisions of the Arizona Court of Appeals considered whether, in light of the Arizona Medical Marijuana Act, the smell of marijuana, standing alone, was sufficient to establish probable cause. The two divisions promulgated contradicting policies, which should be addressed to help clarify the law. This Note will provide a synopsis of the two cases as well as an overview of the approaches taken by comparable jurisdictions. This Note advocates for the adoption of an “odor-plus” standard, one that requires the finding of some fact(s), in addition to the smell of marijuana, before probable cause is met. This standard better balances the competing interests of law enforcement and the privacy rights of individuals. This Note will propose that the “plus” may be satisfied by focusing on the general probability of illegal use. Using statistics, this Note will suggest the probability that in specific instances, when the smell of marijuana is present, the smell is coming from an illegal source not exempt under the Arizona Medical Marijuana Act. However, if statistics shift or the law changes, the odor-plus standard would present a fluid doctrine, where probable cause can be met by other facts that establish the probability of finding the illegal use or possession of marijuana.