The present invention relates to a process for the preparation of diaminobutane from ornithine, comprising steps of: i. preparing a solution of (a) a salt of ornithine and an acid; and (b) an aldehyde or a ketone, or a mixture thereof; in (c) a solvent, wherein the solvent comprises a protic organic solvent or a dipolar aprotic organic solvent, or a mixture thereof and ii. heating the solution to a temperature above 100° C., thereby inducing decarboxylation of the ornithine and formation of diaminobutane.