A novel class of alkoxy-acyl carnitines, wherein the alkoxy-acyl radical has from 4 to 6 carbon atoms (tipically: methoxypropionyl, ethoxypropionyl and propoxyacetyl) is prepared by reacting a solution of a carnitine salt in an organic solvent with an alkoxy-acyl halogenide, thus obtaining the corresponding salt of alkoxy-acyl carnitine. By eluting an aqueous solution of this salt through a column of an ion exchange resin activated in Cl.sup.- or Br.sup.- form, the chloride or bromide of alkoxy-acyl carnitine is obtained. The alkoxy-acyl carnitines are therapeutically effective in the treatment of cardiac disorders, hyperlipidaemias and hyperlipoproteinaemias.