It has been increasingly recognized that adenosine-5'-triphosphate (ATP) signaling through P2 purinergic receptors has a diverse influence on cell functions and human health. In this contribution, a simple and non-invasive method to specifically label P2 receptors using ATP-conjugated quantum dots (QDs) is demonstrated. In addition, the endocytosis, vesicular trafficking, and recycling of QD-labeled P2 receptors are studied under different physiological conditions using confocal and total internal reflection fluorescence microscopy.