Shape measurements in horticultural research have generally been expressed as ratios or indexes. Computer-based image analysis enables the objective quantification and statistical analysis of two-dimensional sample shape variability. In addition, the availability of public domain software facilitates the inexpensive but accurate quantification of object shape in horticultural research. We describe the procedures for measuring sample shape using the following publicly available software: ImageJ, ImageTool, and SHAPE. Using U.S. #1 sweetpotato storage root samples from plots subjected to various weed control treatments, we detected significant differences in elongation, compactness, as well as shape attributes. We also measured size and shape variability from representative fruit, leaf, and floral organ samples. The results demonstrate that, where possible, measurement of two-dimensional samples can be undertaken inexpensively and accurately using public domain software applications.