A fiber-optic contact probe near infrared spectroscopy (NIRS) instrument is evaluated to predict fat, moisture and protein in intact Iberian pork loins. A total of 173 Iberian pig loin samples were analyzed. Spectra from intact loins were collected with a LabSpec®Pro A108310 spectrometer (Analytical Spectral Device) and from the ground meat with a FossNIRSystem instrument. Spectra attenuation was required for removing very signal noise areas in the intact loin spectra. As reference values were used the NIRS predictions of the sample set estimated with a robust calibration model for ground samples and analyzed in a FossNIRSystem instrument. Modified Partial Least Squared (MPLS) regression was performed and different spectra pretreatments and spectral regions evaluated. The range 450-2300 nm performed the best models for the instrument evaluated, showing a suitable potential of the NIRS instrument for on-line analysis of pork loins.