OBJECTIVE: Despite increased public awareness and use of opioid agonist therapy (OAT), there is little published data on contraception among women on methadone or buprenorphine/naloxone. This study aimed to characterize patterns of contraception use among this population. METHODS: We conducted a cross-sectional survey between May 2014 and October 2015 at 6 medical clinics, pharmacies, and community organizations in British Columbia. Trained surveyors used the Canadian Sexual Health Survey (CSHS) to collect information on contraceptive practices and barriers to health care access. Descriptive analysis was performed on the subset of women on OAT who were at risk for unintended pregnancy. RESULTS: Of the 133 survey respondents, 80 (60.2%) were at risk for unintended pregnancy. Among the 46 respondents with a recent pregnancy, 44 (95.7%) reported it as unintended. Of those at risk for unintended pregnancy, the most common contraceptive methods used were "no method," male condom, and depo-medroxyprogesterone at 28.8%, 16.3%, and 12.5%, respectively. Only 5% reported dual protection with a barrier and hormonal or intrauterine method. Barriers to contraception access included difficulty booking appointments with providers and cost, although 97% of all respondents reported feeling comfortable speaking with a physician about contraception. CONCLUSION: We found that most respondents using OAT reported prior pregnancies that were unintended, and used less effective contraceptive methods. Health care professionals who provide addiction care are uniquely positioned to address their patients' concerns about contraception. Incorporating family planning discussions into OAT services may improve understanding and use of effective contraceptive methods. Addressing unmet contraceptive needs may enable women on OAT to achieve their reproductive goals.