Bone retouchers are the most common tools for processing lithic raw material in the Middle Paleolithic of Eurasia. Typically, they are perceived by Paleolithic researchers as informal, unmodified tools made from bone blanks accidentally obtained during the extraction of marrow. In this article, we introduce new data on a large collection of bone retouchers from Chagyrskaya Cave (in the Altai Mountains). Their dimensions demonstrate a high standardization of blanks, indicating the intentional selectivity of Neanderthals. Selection also concerned animal species and the anatomical positions of bones. We found that morphological characteristics such as the number of active areas and the degree of their modification did not affect the size of the retouchers and attest only to the reorientation of tools during lithic processing. In the course of retouching, cross-sections of diagnostic traces in the active areas underwent significant changes: whereas at the early stages they reveal “furrows” with V-shaped cross-sections, multiple blows against the processed lithic resulted in the deformation of the original form, which eventually resembled an upturned trapeze. The comparison of bone retouchers from several multicultural Middle Paleolithic complexes in Eurasia (Chagyrskaya and Denisova caves in the Altai, Kabazi V site in the Crimea, and Barakayevskaya Cave in the Caucasus) evidences similar proportions but considerable variation in size. Proportions, then, are an inherent functional characteristic of bone retouchers, which does not depend on either the cultural context or the raw material base.