The cross-metathesis of methyl 10-undecenoate 1 derived from castor oil as a renewable raw material with diethyl maleate 2 was investigated. These reactions were carried out with several phosphine and N-heterocyclic carbene ruthenium catalysts. The reaction conditions were optimised for high conversions in combination with high cross-metathesis selectivity. This single-step and atom-economic synthetic method illustrates an efficient and selective preparation procedure of linear α,ω-dicarboxylic acid esters starting from renewable resources and comparatively inexpensive base chemicals. Further by-products are hardly obtained due to their consumption in secondary metathesis reactions. Hence, a sustainable alternative for polyamide and polyester monomers is presented.