The aim of this work was to study abstinence rates and withdrawal effects of rapid detoxification of opioid-dependents under general anaesthesia (RD-GA) compared to standard methadone tapering (SMT) using a prospective clinical trial with a follow-up of 3 months, as a preliminary study at the Novadic addiction centre in St Oedenrode and St Joseph Hospital in Veghel, the Netherlands. Thirty opioid-dependent patients took part. Outcome measures included urine toxicology screening for opiates to determine abstinence and presence of objective and subjective opioid withdrawal distress symptoms. Statistically significant differences in abstinence rate between RD-GA and SMT were present after one (RD-GA 100% vs. SMT 40%, p <0.01) and 2 months (RD-GA 93% vs. SMT 33%, p <0.01). After 3 months the difference in abstinence was still substantial, but no longer statistically significant (RD-GA 67% vs. SMT 33%, p =0.14). Objective and subjective withdrawal symptoms showed largely identical outcomes and were equally low in the two groups for those who remained in the study. There was a considerably higher percentage of abstinence in the RD-GA group after 1, 2 and 3 months of follow-up accompanied by relatively mild withdrawal symptoms of shorter duration. However, if one completes SMT the data suggest a greater chance of staying clean in the long term than those completing RD-GA.