We investigated the spatio-temporal profile of visual-tactile integration during crossmodal reaction time and congruency tasks. EEG activity was recorded from intracranial surface and depth electrodes in 8 patients. In a subset, we recorded responses from linear arrays of 24 laminar microelectrodes. Subjects were stimulated with brief tactile taps on the thumb and index finger with simultaneous LED flashes at the same locations. Each task employed eight stimulus conditions that consisted of bimodal congruent, bimodal incongruent or unimodal tactile or visual stimulation. The target modality varied between blocks. In Experiment I, subjects made speeded button responses to any stimulus in the target modality, irrespective of location. In Experiment II, subjects were instructed to make speeded elevation discrimination responses to stimuli in the target modality. Macro- and microelectrode data were analyzed in the time and frequency domains to compute ERPs and event-related power changes in broad frequency bands. Based on the microelectrode data we estimated population transmembrane currents and multi-unit activity in specific brain areas. We report the timing and laminar profile of multisensory interactions in the human brain and their modulation by task requirements and attention.