The current research tests stage-sequential models of safer sexual behavior using a new method for data analysis called Latent Transition Analysis (LTA). Results are presented from data collected on 359 injection drug users participating in a seroconversion study conducted by the UCLA Drug Abuse Research Center. We identified a six-stage model that adequately represented the data. Results indicate that respondents moved back and forth among high, medium, and low risk stages. This finding highlights the need for continual, sustained interventions to help maintain safer sex and drug-using behaviors in high-risk groups.