A spelling-age match design was used to test the hypothesis that deficits in phonologically related skills may be causally related to difficulties in acquiring basic spelling knowledge. Poor grade 5 spellers, average grade 3 spellers, and good grade 2 spellers matched on a standardized spelling test, and a group of good grade 5 spellers matched by chronological age with the poor grade 5 spellers were administered a phonemic segmentation test containing nondigraph pseudowords and an experimental spelling test containing words of the following four types: exception, ambiguous, regular, and pseudowords. Consistent with the hypothesis, it was found that when compared with the poor spellers, the average and good spellers performed better on the phonemic segmentation task, made fewer errors in spelling pseudowords, and made spelling errors that were more phonetically accurate.