The crystallization temperatures of two binary systems - tetradecane + hexadecane and tetradecane + pentadecane - were measured under high pressure up to 100MPa using a polar microscopy device. The slopes of the melting curves in the (T, P) diagram show a dependence on the nature of the different solid phases that can appear. The effect of pressure on the liquidus curve in a (T, x) diagram is discussed and represented in the last part of this work with an excess Gibbs energy model, slightly modified to take the different solid phases into account. (c) 2005 Elsevier B.V. All rights reserved.