Cashiers' identification-checking behaviors were observed at two grocery stores with the aim to actively involve cashiers in decreasing credit-card fraud. After baseline observations, cashiers at one store received a participative goal-setting and feedback intervention, whereby they collaboratively set a store goal for checking customers' identification. Over 23 days, the cashiers received one-to-one verbal feedback on their store's identification-checking percentages. The percentage of identification-checked purchases at the intervention store increased from 0.2 percent at Baseline to 9.7 percent during the Intervention. Then, it declined to 2.3 percent during Withdrawal, showing functional control of the intervention over the cashiers' target behavior. The cashiers at the other store served as the control group, and their percentage of identification-checked purchases were 0.3 percent, 0.4 percent, and 0.7 percent respectively during each of the A-B-A phases at the intervention store. It was also found the intervention affected male cashiers more than female cashiers. The present study also assessed the social validity of the current intervention by surveying both customers and cashiers from the intervention store. The results showed that customers do not mind getting their ID checked, while cashiers consider it important to check a customer for identification during a credit purchase.