Olfaction is now recognized as having a pervasive influence on human social cognition (e.g. de Groot, Semin, & Smeets, 2017). Human body odors have been found to modulate the perception of both invariant (e.g., attractiveness, trustworthiness, etc.) and transient (e.g., emotional expressions) face characteristics (for review, see Damon et al., 2021). Here, we examined whether body odor of self or romantic partner influenced a face discrimination mechanism: the sensitivity to facial identity information. We assessed whether exposure to (axillary) odor cues could sharpen the facial perception of related identity compared to a control odor condition, and lead participants to rely on smaller amount of visual information to recognize identity in faces. We assessed identity discrimination thresholds (i.e. Just-Noticeable Difference, JND) for self and romantic partner faces by measuring the JND between a prototypical face and self or romantic partner faces mixed with the prototype with various identity ratios, using a 2-interval forced-choice task with an adaptive psychophysical method (i.e. the psi method). Results showed that both self and partner body odors facilitated the perception of related identity, F(1, 23) = 7.84, p = .010, η²p = .25, as participants showed smaller JND during exposure to body odor compared to neutral odor. Overall, exposure to the body odor of a familiar individual led to more fine-grained visual processing of related facial identity. Significant positive correlations between the baseline JND (i.e. with a neutral odor) and the magnitude of the odor effect (i.e. the difference in JND between the odor and neutral conditions) further suggest that the higher the JND, the stronger the influence of the odor, r(22)= .57, p = .003, and r(22) = .46, p = .025, for self and partner odor, respectively. These results accord well with the inverse effectiveness rule, stating that multisensory integration increases as a reverse function of unisensory responses.