A new sustained-release dosage form of nitrofurantoin as microcapsules was prepared by carboxymethylcellulose aluminium sulphate simple coacervation technique. In vitro release studies for microcapsules and their formulated hard gelatin capsule and tablet forms were performed. Release rates were studied as functions of core:wall ratios and the particle size's of the microcapsules. Dissolution tests of microcapsules and their dosage forms were studied in simulated gastric and intestinal media without enzyme using the USP XXI basket method. Release data were examined kinetically and the ideal kinetic models were estimated for drug release. In addition, optical and electron scanning microscopic works were carried out on the microcapsules.