A simple turn-on fluorescence strategy is proposed for the detection of ATP based on DNA-stabilized copper/silver nanoclusters (DNA-Cu/Ag NCs). The fluorescence intensity of DNA-Cu/Ag NCs increases significantly in the presence of ATP, because the specific interaction between ATP and its aptamer causes two darkish Cu/Ag NCs to be situated at the 5' and 3' termini close to each other. A limit of detection (LOD) of 7.0 μM is found, in a linear range of 2-18 mM, and the proposed sensor is simple, sensitive, and selective. Additionally, the DNA-Cu/Ag NCs/ATP system is further developed into a sensor for ADA detection and demonstrates a linear response to ADA from 5 to 50 U/L with a LOD of 5 U/L. The proposed method is also shown to be successful in detecting ATP and ADA in a solution of fetal bovine serum.