This study reports on the preparation and evaluation of cyclophosphamide loaded-polyalkylcyanoacrylate nanospheres obtained by emulsion polymerization. Characterization by differential scanning calorimetry, infrared spectroscopy and X-ray diffraction can reveal state dispersion of the drug inside the nanospheres. Such information predicts the stability of the particles and the drug release behaviour. The study has indicated the prescence of a molecular dispersed system. The drug release behaviour was also studied.