Importance: Medical and nonmedical cannabis use and cannabis use disorders (CUD) have increased with increasing cannabis legalization. However, the prevalence of CUD among primary care patients who use cannabis for medical or nonmedical reasons is unknown for patients in states with legal recreational use.

Question: What is the prevalence of cannabis use disorder (CUD) among primary care patients who use cannabis in a state with legal recreational cannabis use, and does prevalence differ by reason for use?

Findings: In this cross-sectional study, weighted prevalence of any CUD did not vary by reason for cannabis use, whereas the prevalence of moderate to severe CUD did. Prevalence of moderate to severe CUD was higher in those who reported nonmedical use only or both medical and nonmedical use.

Meaning: In this study, CUD was common among patients who use cannabis in a state with legal recreational cannabis use, with moderate to severe CUD most prevalent among patients with any nonmedical use.