The invention relates to a method for validating a biometrical acquisition, mainly the acquisition of a body imprint of a body area such as fingerprints or a face imprint, wherein the method involves together with the biometric acquisition: lighting the body area using at least one radiation having at least two respective different wavelengths between approximately 500 nm and 1150 nm; taking at least two reflectometry measurements concerning said and at least two wavelengths for measuring the reflection index of the tissues for these wavelengths; calculating the ratio for two measured indices; and comparing the ratio with a range of reference values characterizing a haemoglobin-containing living tissue in terms of proportions of oxygenated and non-oxygenated forms characteristic of the living states for the wavelengths in question; if the ratio is included in said range, the body area is considered as living and the biometrical acquisition is validated; and conversely, if the body area is considered as not living, the biometrical acquisition cannot be validated.