One promising avenue for the atom-efficient synthesis of amides is solvent-free direct thermal amidation. More than 140 years ago, Hoffman reported that amides can form by heating ammonium salts of aliphatic acids at 230 °C under high-pressure. Nevertheless, direct thermal amidation has been studied in the literature only scarcely. In 1989, Cossy and Pale-Grosdemange reported the synthesis of amides in high yields by heating carboxylic acids and primary amines in the presence of molecular sieves at temperatures of 140-180 °C. The role of molecular sieves was to trap the forming water molecules, and the protocol was limited to primary amines, whereas secondary amines only yielded ammonium salts. Jursic and Zdravkovski showed that by heating primary amines and carboxylic acids at 160-180 °C a variety of amides could be formed as long as water was continually eliminated from the reaction mixture, thus shifting the equilibrium towards the amide formation. Despite these early works showing great promise, direct thermal amidation has been somewhat neglected in the literature and considered to be limited to simple substrates. In the search for atom-efficient amide synthesis methodology, we have turned to mechanochemical ball milling. Solvent-free or minimum-solvent mechanochemical reaction environment is known to have tremendous sustainability benefits and is known to be effective in the synthesis of amides. Here we present a conceptually different approach, which involves the thermo-mechanochemical treatment of carboxylic acids and amines for the quantitative conversion to amides without additives. Moreover, we managed to observe and characterise ammonium carboxylate salts as crystalline reaction intermediates preceding the amide bond formation. We applied our protocol for the synthesis of a commercial pharmaceutical amide moclobemide and obtained it in a quantitative manner directly from the milling jar.