The invention provides compositions that are NO-releasing polymers or low-molecular-weight NO-releasing compounds. The invention also provides the secondary amine polymers that are the precursors as well as the products of the NO-releasing polymers. The invention provides methods of making the secondary amine polymer precursors and the NO-releasing polymers. The invention provides methods for the nitrosation of low-molecular-weight amines and secondary amine polymers to form the corresponding low-molecular-weight NO-releasing compounds and polymers.