Aminoalcohol lipidoids are prepared by reacting an amine with an epoxide-terminated compound are described. Methods of preparing aminoalcohol lipidoids from commercially available starting materials are also provided. Aminoalcohol lipidoids may be prepared from racemic or stereochemically pure epoxides. Aminoalcohol lipidoids or salts forms thereof are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the amino moiety of these aminoalcohol lipidoid compounds, they are particularly suited for the delivery of polynucleotides. Complexes, micelles, liposomes or particles containing the inventive lipidoids and polynucleotide have been prepared. The inventive lipidoids may also be used in preparing microparticles for drug delivery. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.