Potato tuber size and shape are important agronomic traits, especially for making and maintaining high-quality and consistency of processed foods such as French fries and potato chips. However, unlike grain crops, continuous variation of potato tuber size and shape are commonly observed among tubers even though a potato crop is considered genetically identical due to its clonal propagation (Van Eck et al. 1994). Consequently, measuring the tuber size and shape of many samples of a single potato breeding clone across environments and years becomes necessary to identify new potato varieties showing improved consistencies in tuber size and shape. Even though the two traits are commercially important, an economical and high-throughput tuber size measurement method has not been available. Therefore, we are introducing an image-based potato tuber size measurement (IPTSM) system, based on R statistical software (R Core Team 2018) with the package EBImage (Pau et al. 2010). The algorithm automates tuber detection in images and reports tuber shape values such as the length to width ratio. The strong point of the IPTSM is that the sizes of several or more tubers can be measured at once within a short time. Ten tubers of each of 192 progeny of family A08241 and their two parents were measured (Total 1920 tubers) to confirm the accuracy of IPTSM, by both a digital caliper and IPTSM. Images were collected with a standard digital camera (Nikon D7100) and color card (X-Rite ColorChecker Classic), in a software-controlled lightbox (Havox Photo Studio HPB-80D). Data collection and comparison are ongoing, with a preliminary assessment presented.