High pressure freezing processes such as pressure assisted freezing (PAF) and high pressure shift freezing (HPSF) are novel technologies that can be used to improve the quality of frozen foods. A one dimensional finite difference numerical model based on the enthalpy formulation was developed to simulate high pressure freezing of tylose, agar gel and potatoes. The Schwartzberg equation was used in the prediction of both the initial freezing point and the temperature evolution below freezing. Results showed that the model can satisfactorily describe the PAF and HPSF processes. When compared under similar heat transfer conditions, the phase transition times for HPSF were shorter than those at atmospheric pressure. The amount of ice instantaneously formed upon pressure release and the total freezing times were also determined by the developed model and were in reasonable agreement with the experimental data in the literature. (C) 2008 Elsevier Ltd. All rights reserved.