As part of a larger syringe access and HIV risk study, a subsample of 23 current injection drug users completed daily diaries, highlighting activities related to syringe acquisition, use, and discard. Diaries have been previously utilized in a variety of psychological, public health, and nutrition studies to assess risk as well as correlated behaviors. We piloted the diary methodology in three northeastern U.S. cities (Hartford and New Haven, CT, and Springfield, MA) to learn about correlates of HIV risk. We discovered that the method provided advantages over several other qualitative and ethnographic methods. Results indicate that daily diaries elucidated (1) patterns of injection drug use, (2) sporadic and high-risk events, (3) HIV and hepatitis risk related to the syringe life cycle, and (4) emotional correlates of drug use. Furthermore, we witnessed an unexpected intervention effect that the diary may have in the lives of drug users.