This paper examines the relative effectiveness of forming implementation intentions (i.e., making specific plans regarding how to go about achieving a goal) for increasing goal attainment under regulatory fit vs. nonfit. We discuss and empirically test the proposition that regulatory nonfit increases the effectiveness of implementation intentions. Extant research contrasts goals of differing difficulty (e.g., buying a textbook vs. finding an apartment) in order to test the relative effectiveness of implementation intentions. In contrast, the present study focuses on identifying the change in implementation intention effectiveness for the same goal (i.e., collecting and turning in receipts for a reward) under conditions of fit vs. nonfit. We empirically demonstrate that when faced with the same goal, people who experience regulatory nonfit perceive the task to be more difficult to complete than people who experience regulatory fit. In turn, when the task is perceived as being more difficult, implementation intentions prove more effective to enhance goal attainment. Our study provides insight into the interaction between regulatory fit and implementation intentions and subsequent effects on goal attainment.