Seventy-two recent-onset injection drug users and 241 non-injection drug users were recruited in Quetta and Lahore, Pakistan, in 2003. Trained interviewers administered questionnaires regarding drug use behaviors and perceived changes in drug cost/supply. Logistic regression identified independent correlates of recent-onset injection. In Lahore, a perceived increase in drug cost was associated with higher odds of recent-onset injection, with no association in Quetta. Recent-onset injection was also associated with family history of drug use, group drug use, and sharing snorting/chasing tools. Changes in perception of the drug supply may be associated with recent-onset injection drug use. Familial/social influences were also associated with recent-onset injection, suggesting peer-led interventions could discourage transition to injection drug use.