We examine lithic artifacts from Late Neanderthal site Sesselfelsgrotte (Bavaria, Germany) to evaluate the possibility of fire-use and the intentional flint heat treatment performed by Late Neanderthals. We analyzed 1,113 flint pieces from the G-Layers-Complex (~ 60 to 45 kya; Micoquian), and 946 from the Lower-Layers-Complex (~ 115 to 70 kya; Mousterian), based on macroscopic traits associated with the exposure of flint to fire, assigning artifacts to one of three groups: burnt, unburnt, and possibly intentionally heated. Our results show that while both complexes demonstrate clear presence of fire, fire is more common in the younger G-Layers-Complex. Moreover, possibly intentionally heated pieces are significantly more frequent in the G-Layers-Complex, especially among the tools, and specifically among side scrapers, proposing a link between heat treatment and the production of these tools, most probably due to their functional and cultural significance. We therefore suggest the intentional heat treatment of flint in the G-Layers-Complex of Sesselfelsgrotte. The proportions of burnt flint artifacts in both sequences suggest an intensification in fire-use at the site over time, while the appearance of possibly intentionally heated artifacts in the G-Layers-Complex suggests the development of this advanced pyro-technology by Neanderthals, sometime between these two timeframes. Our results are supported by sedimentological and faunal data. We view these results as further indication for the advanced cognitive and technological capabilities of Neanderthals, such that did not fall from these of Early Modern Humans.