This paper examines the functional contribution of medial premotor cortex, the supplementary motor area (SMA), to visuo-spatial transformation. Previous studies have found evidence of activation in SMA using 'mental rotation' tasks in which subjects make mirror-image judgements about simultaneously presented depth rotated novel forms. This manipulation induces potential confounds in the cognitive demands of the task in addition to spatial normalization processes. We clarify the role of SMA in visuo-spatial normalization using functional magnetic resonance imaging with a sequential mirror-image judgement task involving 2D image-plane rotated forms. The results show preferential activation of pre-SMA, as well as the ventrolateral prefrontal and parietal cortex during the visuo-spatial transformation of mirror-image stimuli.