Method of gravimetric filling of a solid product in sterile conditions in a pharmaceutical container (1) of small dimensions including syringes, vials, capsules, ampoules, single-dose devices, inhalers, bottles, carpules blister, sachets or bags with solid substances selected from the group formed by powder, lyophilizate, granules, pellets, nanoparticles or microparticles. More particularly, it relates to a process for the gravimetric filling of pharmaceutical containers (1) with one or more sterile solid pharmaceutical substances or sterile excipients dosed and prepared in an aseptic environment.