Do initiation patterns of opioids vary by birth cohort? Given the changes in prescription opioid availability over time, a new study hypothesized that recent birth cohorts (after 1980) are more likely to initiate opioids through the misuse of prescription opioids, not through heroin. This study tested this hypothesis using two samples—1) data from recruited subjects that inject drugs (n=483); 2) general population data from the National Survey of Drug Use and Health (n=1264). In both study samples, data were collected from 2011-2013 and utilized birth cohort data from only individuals that reported lifetime use of both prescription opioids and heroin. Statistical analyses revealed differences among birth cohorts in the prevalence of individuals that initiated opioids, with similar findings reported across both data sets. For example, as the four birth cohorts progressed (pre-1960s; 1960-1969; 1970-1979; 1980 and after), the prevalence of opioid initiation through heroin gradually decreases. During this same time period, the data reveals a concomitant increase in opioid initiation through prescription opioids. Take Away: This study suggests more recent birth cohorts (after 1980) are more likely to initiate opioids through prescription opioid misuse, rather than through heroin. The authors argue that monitoring the pattern of opioid initiation in future studies will remain valuable, especially as emerging public health policies limit the availability and accessibility of prescription opioids.