The present invention provides lipidoids that can be used to modulate the immune response in a subject. Lipidoids are prepared by the conjugate addition of an amine to an acrylate to acrylamide. The lipidoids form complexes or particles with an immunostimulatory polynucleotide, which are then administerd to a subject. Such compositions have been found to stimulate the production of cytokines and increase both humoral and cell-mediate immune response. The invention also provides pharmaceuti-cal compositions thereof and methods for using the same.