Background: Part of the variability in treatment outcomes for Motivational Interviewing (MI) may be explained by differences in the fidelity to MI. The Motivational Interviewing Treatment Integrity manual version 4 (MITI 4) is an improved measure of fidelity to elements of MI. It is not known whether the fidelity to MI, as measured by the MITI 4, is related to treatment outcome. Objectives: To examine whether fidelity to MI is associated with alcohol use outcomespredictive validity of the MITI 4. Method: Twenty percent of the recorded sessions at the Danish sites of the Elderly Study were randomly drawn and coded for fidelity to MI with the MITI 4. The Elderly Study was an international, randomized controlled trial, in which people 60 years or older with Alcohol Use Disorders received either four weeks of Motivational Enhancement Therapy (MET) or four weeks of MET combined with up to eight additional sessions of the Community Reinforcement Approach-Senior (MET+CRA-S). Elements of MI and summary scores of the MITI 4 were used as predictors in a mixed effects regression analysis. Treatment outcomes were use of alcohol and consequences of drinking at 26-weeks follow-up. Results: In total, 423 sessions representing 238 participants were randomly drawn and coded for fidelity to MI. Mean values of the treatment elements indicated high fidelity to MI, with higher fidelity to MI in the MET sessions, as compared to CRA-S sessions. None of the predictors in the multilevel model analyses were associated with outcome at follow-up. Exploratory analysis indicated reverse associations between one measure of MI-fidelity and drinking outcomes in the combined treatment (CRAeS). Conclusion: The fidelity of the MI intervention, received by participants in this study, did not predict better treatment outcomes. MI may be less effective in populations which are already committed to change behavior. As expected and validating for the MITI 4, fidelity to MI-elements was lower in the combination of MI with other treatment approaches. Additionally, the timing of MI in these combined settings might be important for effectiveness.