Background: The Inventory of Physical Activity Barriers (IPAB) assesses physical activity participation barriers. Development, refinement, and psychometric evaluation of the IPAB occurred via an electronic format. However, various circumstances may require using a pen-and-paper format. As instrument formats are not always interchangeable, the authors aimed to establish whether 2 different formats (electronic and pen and paper) can be used interchangeably for the IPAB. Methods: This randomized crossover study included 66 community-dwelling adults aged 50 years and older (mean age = 73 [SD = 7.6]). Half the sample completed the electronic format of the IPAB first and the pen-and-paper format second, and the other half completed them in reverse order. Tests of equivalence and a Bland–Altman plot were performed. Results: The intraclass correlation coefficient between formats was .94, and kappa was .68. The mean difference between the 2 administration forms of the IPAB was 0.002 (P = .96). Both administration formats had high internal consistency (Cronbach alpha = .92 and .93) and illustrated construct validity (P ≤ .001 for both administration formats). Conclusion: Pen-and-paper and electronic formats of the IPAB are equivalent and, thus, can be used interchangeably among non-Hispanic whites who are highly educated. The format should be used consistently if completing preintervention and postintervention evaluations or comparing scores.