The patterns of spelling disorder seen amongst the developmental dysgraphias argue for the separability of spelling mechanisms during acquisition. Such dissociations may currently be incorporated in a relatively straightforward fashion within multiple route models. Models of adult spelling systems have been less well developed and discussed than models of reading systems. Traditional developmental stage models of spelling acquisition are not able to successfully account for the variable patterns of the developmental dysgraphias. In the cognitive neuropsychological analyses of the developmental dysgraphias detailed here, no assumptions about reading skills are made. Two contrasting disorders of spelling developmental surface dysgraphia and developmental phonological dysgraphia, seen in children of similar ages, who also have similar spelling ages will be discussed in relation to the model depicted. Orthographic skills involve sophisticated spelling systems and would be necessary for the spelling of irregular words. Overall, the models of the adult spelling system are a helpful background against which to discuss spelling disorders in children.