In an orally presented vowel length categorization task with both word and nonword stimuli, a group of 10-year-old German-speaking poor spellers performed less accurately and consistently slower than a group of normal spellers of the same age. The poor spellers' level of performance was comparable to that of a group of 8-year-old inexperienced spellers. In an experimental design, the influence of the phonological characteristics of the preceding and succeeding consonant on children's decisions about vowel length was examined. The type of onset had hardly any effect whereas the offset consonant had a marked influence. It is concluded that vowel length categorization is associated with the ability to mark vowel length in spelling. Vowel length predicts but is not sufficient to explain difficulties in orthographically correct spelling of vowel length.