Two experiments examined the role of syllables in writing Spanish words. In Experiment 1, participants had to write single words that were aurally presented. The interletter intervals (ILIs) between critical letters were measured. Longer ILIs were found in the intersyllabic than the intrasyllabic condition. In Experiment 2, the inputs were pictures to remove any potential phonological bias stemming from the input stimulus. Results suggested that the linguistic nature of the input is not determining the output. Post hoc analyses revealed that other characteristics of the stimuli cannot explain the results. These results indicate that syllables are essential units of processing in writing Spanish and that central processes related to spelling and the graphemic buffer affect peripheral processes at movement execution.