Two models that seem to explain the acquisition of behavior, such as drug use, and behavior change are the Stages of Change model and the Multi-Component Motivational Stages (McMOS) model. These models have been used to examine the "Stages of Acquisition" and the "Stages of Habit Change" within a variety of populations. The current study examined the Stages of Acquisition of drug use in upper elementary school students. This study proposes a modification of the Stages of Habit Acquisition as theorized in the McMOS model. The modification is the inclusion of a new stage that is named the Recontemplation Stage. This stage includes those individuals who have tried the substance, but after trying the substance, decide not to try the substance again. This new model, the Modified Stages of Acquisition model, includes six discrete cognitive stages: precontemplation (those who have not tried the substance and are not planning to try the substance); contemplation (those who have not tried the substance but are thinking about trying it some time in the future); recontemplation (those who have tried the substance but are not planning to try it again); initiation (those who have tried the substance and are planning to try/use it again soon); action (those who have been using the substance for a short period of time); and maintenance (those who have been using the substance for a long period of time). The subjects in the study were 811 students from 17 elementary schools in Arkansas and Missouri. The instrument elicited information regarding the stages of acquisition and individual self-reported drug use. The data were analyzed using frequency, distribution, discriminant analysis, and correlation analyses. Stage placement was confirmed by using a series of drug-use measures. Results confirmed the existence of discrete stages of acquisition. This supports the concept of gateway drugs, in that subjects indicated they had progressed further through the stages of acquisition of alcohol use than through the stages of acquisition of cigarette use, smokeless tobacco use, or marijuana use. 5 tables and 18 references