The aldol condensation of citral with acetone catalyzed by a Mg,Al-mixed oxide derived from hydrotalcite with an Al/(Al + Mg) molar ratio equal to 0.2 was studied. The influence of reaction parameters such as acetone/citral molar ratio (1-5), temperature (343-398 K), and reaction time (30-240 min) was evaluated aiming at their optimization to increase pseudoionone production with high selectivity. The best results were obtained for an acetone/citral molar ratio of 5 with 5 wt.% of catalyst (based in the total weight of reactants). The highest pseudoionone selectivity (90%) was achieved at 343 K after 4 h of reaction, with a citral conversion close to 50%. The observed trends suggest that higher conversions and selectivities should be attained at longer reaction times at 343 K. GC-MS analyses confirmed pseudoionone isomers as the main reaction products, the by-products being those from the aldol condensation between pseudoionone and acetone and from the self-condensation of citral. A general reaction scheme is proposed. (c) 2005 Elsevier B.V. All rights reserved.