Mg-Al-O-But–Hydrotalcite is found to be a mild and efficient catalyst for the cyanoethylation of alcohols and thiols in quantitative yields. Exclusive synthesis of 3-alkoxypropionitriles or 3-alkylmercaptopropionitriles is realised by compatible basic sites of Mg-Al-O-But–Hydrotalcite. The present ecofriendly catalytic system is a potential alternative to soluble bases.