The past couple of decades have witnessed a rapid growth and still increasing interest in research on multisensory processing at behavioral and neural levels, which has led to findings of multisensory influences even in primary sensory cortical areas. The study reported here is a logical continuation of a previous study investigating individual differences in multisensory enhancement of behavioural pitch discrimination. The previous study showed an association between the magnitude of the visually-induced gain and individual pitch discrimination thresholds, in accordance with the multisensory principle of inverse effectiveness. The present study used magnetoencephalography (MEG) and the magnetic counterpart of the mismatch negativity (MMNm) to test the hypothesis that a similar pattern would be observed at the pre-attentive level of neural processing. The amplitude of MMNm served as an index of sensitivity. MMNm responses from 45 participants with varying levels of pitch discrimination abilities had significantly larger amplitudes in conditions with either crossmodally compatible or incompatible visual deviants compared to the condition where the visual information did not differ from the standard. Hence, results confirmed that multisensory response amplification is present already at early levels of perceptual processing and, as predicted by the principle of inverse effectiveness, that the visually induced gains were larger in participants with weaker MMNm responses to auditory-only deviants. The study adds to the body of literature showing that the auditory cortex is not immune to non-auditory inputs. In addition, it brings novel findings to the field by showing larger visually induced neural enhancements in participants with lower auditory sensitivity. As such, our findings highlight not only the importance of considering multisensory influences on so-called sensory-specific experiences, but also that inter-individual differences in multisensory processing exist and may be partly explained by differences in unisensory processing abilities, beginning already at an early level of perceptual processing.