This work demonstrates the application of FT-NIR spectroscopy in order to monitor the enzymatic interesterification process for butterfat modification. The reactions were catalyzed by Lipozyme TL IM at 70 degrees C for the blend of butterfat/rapeseed oil (70/30, w/w) in a packed-bed reactor. The blend and interesterified fat samples were measured in liquid form at 70 degrees C by transmission mode-based FT-NIR over the spectral region 12000-4000 cm-1. The calibration of FT-NIR for conversion degree (evaluated by the triglyceride profile, which was represented by the triglyceride peak ratio) and solid fat content (SFC) of the interesterified products was carried out using partial least squares (PLS) regression. Good correlations were observed between the NIR spectra and ln (peak ratio), and between the NIR spectra and the SFC at 5 degrees C over the spectral range 5269-4513 cm-1. Overall, transmission-mode FT-NIR spectroscopy performed at 70 degrees C yielded conditions close to those used during the interesterification process, implying that this method could be used to control the enzymatic interesterification process online.