For the use of insemination dose of frozen-thawed boar sperm at the commercial level, it would be very interesting to know, in advance, if sperm from a boar will freeze well or poorly. So the aim of this study was to evaluate the ability of the 'ChemSensor' (gas chromatograph-mass coupled with chemometric analysis software) as an early discrimination tool of Iberian pig ejaculates according to their freezability. For this, 33 ejaculates from Iberian breed boars were used and an aliquot of 1 ml of semen from each one was analyzed with the 'ChemSensor', the rest of the ejaculate was frozen-thawed using a standardized protocol to determine their freezability (good and bad freezers), depending on the percentage of intact plasma membrane and total motile post-thaw sperm. For analysis of 'ChemSensor', sperm samples were volatilized and ionized, decomposing into different ions with a determined size, which were used as discrimination variables to determine if it is possible the separation of ejaculates into two freezability groups. The 'ChemSensor' was able to discriminate all the ejaculates of the good freezers; and inside of bad freezers group only one sample was misclassified. Due to the small number of samples, the distance obtained between groups (2.62), although not very high, it could be considered significant, although a larger sample in order to create a more robust mathematical model would be necessary. In conclusion, the 'ChemSensor' is a possible suitable tool for the early discrimination of Iberian pig ejaculates according to their freezability.