Adenovirus vectors are common gene delivery vehicles for gene therapy. When using these viral vector systems, accurate measurement of the physical and infectious titers is essential for assessing safety. However, even when using specific protocols and reagents to evaluate these parameters, variations in the data generated between laboratories can occur, challenging the ability to compare vector dose, safety, and efficacy. The Adenovirus type 5 Reference Material (ATCC VR-1516) was developed in response to this concern to enable the normalization of laboratory-specific internal reference standards and standardize measurements made by different laboratories.