Abstract: A continuous process for the preparation of gelatin based nanoparticles in a reactor having a process channel having a mixing element therein, the process having the following steps: A) feeding separately an aqueous gelatin solution at a first rate and a water-miscible organic solvent at a second rate to the process channel of the reactor to be mixed therein, to form a suspension of non-crosslinked gelatin based nanoparticles and B) crosslinking the non-crosslinked gelatin based nanoparticles, wherein the sum of the first rate and the second rate is chosen such that the reactor has a mixing efficiency as determined by the Villermaux/Dushman method of between 0.1 and 1.5 and the period from the time point at which the aqueous gelatin solution is fed to the reactor to the time point at which the mixture of the aqueous gelatin solution and the organic solvent contacts the mixing element is at most 15 seconds.