This study was carried out to investigate the effect of beta-cyclodextrin (beta-CD) as a cryoprotectant on the eugenol encapsulated nanocapsules. Nanocapsules (NCs) were prepared by emulsion-diffusion method and frozen at various temperatures (-30 degrees C to 10 degrees C). Physical stability of the NCs was determined by particle size analysis and morphological observation using scanning or transmission electron microscopy before and after freezing or freeze-drying process. Freeze-thawed and freeze-dried NCs without beta-CD were remarkably aggregated. The particle size of NCs without beta-CD was significantly increased as decreasing freezing temperature. On the contrary, NCs with beta-CD were slightly increased in the range of 370-400 nm. Significant particle aggregation was not shown at NCs with beta-CD at all freezing temperatures. In this study, beta-CD could was effective as a cryoprotectant to maintain physical stability of NCs after freezing or freeze-drying. beta-CD could be useful to protect Ncs from freezing stress. (C) 2013 Elsevier Ltd. All rights reserved.