Fine-tuned sensory functions are bases of efficient motor control and learning and typically characterize skilled individuals. Although numerous studies demonstrated enhanced unimodal sensory functions at both neural and behavioral levels in skilled individuals, little is known about their multisensory interaction, especially multisensory integration and selective attention that involve volitional control of information derived from multiple sensory organs. Here, we show unique multisensory interaction functions of expert pianists. Expert pianists and musically untrained individuals performed five sets of intensity discrimination tasks at the auditory and somatosensory modalities with different conditions: (1) auditory stimulus, (2) somatosensory stimulus, (3) congruent auditory and somatosensory stimuli (i.e., multisensory integration), (4) auditory and task-irrelevant somatosensory stimuli, and (5) somatosensory and task-irrelevant auditory stimuli. In the fourth and fifth conditions, participants were instructed to ignore a task-irrelevant stimulus and to pay attention to a task-relevant stimulus (i.e., selective attention). The unimodal intensity discrimination of the pianists was superior to that of the nonmusicians at the auditory modality but not at the somatosensory modality. While the discrimination perception was superior in the condition (3) compared to the better one of the individual unimodal conditions (i.e., conditions 1 and 2) only in the pianists, the task-irrelevant somatosensory stimulus worsened the auditory discrimination more in the pianists than the nonmusicians. These findings indicate efficient processing of multisensory information in expert pianists, which enables to benefit from multisensory integration of the auditory and somatosensory information, but exacerbates top-down selective inhibition of somatosensory information during auditory processing.