In France, General Practitioners (GPs) are widely involved in opiate maintenance treatment (OMT) by initially prescribing buprenorphine and monitoring patients under buprenorphine and methadone. Number of treated patients is around 150,000 with 75% of them treated by buprenorphine. Among the guidelines for improving OMT, urine testing is mandatory for initiating methadone, whereas it is recommended for initiating buprenorphine and during follow-up. Urine drug tests are based on immunoassay techniques and enable a qualitative analysis of the recent drug consumption, with detection based on designated thresholds, allow a better appraisal of drug exposure, before initiating and during OMT. While intrinsic diagnostic value of these tests is already demonstrated, the consequences of carrying out these tests on OMT have not been clearly established. Some studies suggest that patients exposed to drug tests may have a better OMT retention and in patients treated by methadone, performing urine screening tests has been shown to be associated with a mortality risk reduction in a Scottish retrospective cohort of opioid addicts. Actually, despite the recommendations to perform these tests, few GP prescribe tests, and few patients are regularly screened. Availability of commercial kits for urine drug testing in the medical office should improve their utilisation.