Provision of alternative non-drug reinforcement is among the most effective methods for treating substance use disorders. However, when alternative reinforcers become unavailable during treatment interruptions or upon cessation of treatment, relapse often occurs. Relapse following the loss of alternative reinforcement is known as resurgence. One factor that could reduce resurgence is longer duration of treatment with alternative reinforcement, but the available data are mixed. Further, the effects of length of treatment have previously only been examined with food seeking. The present experiments directly examined if duration of treatment impacted the magnitude of resurgence of cocaine or alcohol seeking in rats. First, rats were trained to self-administer cocaine (Experiment 1) or alcohol (Experiment 2) by performing a target behavior. Second, target behavior was extinguished and performing an alternative behavior produced an alternative non-drug (i.e., food) reinforcer. Finally, resurgence was assessed following removal of alternative reinforcement after either 5 or 20 sessions of treatment. Treatment duration did not differentially affect resurgence of cocaine seeking in Experiment 1 or Alcohol seeking in Experiment 2. These results suggest that extended treatment with alternative non-drug reinforcement may not decrease propensity to relapse. Further, these results may have implications for treatment of substance use disorders and for theories of resurgence.