Several studies on children and adults with and without linguistic impairment have reported differences between verb and noun processing. The present study assessed whether noun and verb bases affect differently children's reading of derived words. Thirty-six Italian good readers and 18 poor readers, all 4th or 5th graders, were asked to read aloud nouns derived from either a noun base (e.g., "artista", artist) or a verb base (e.g., "punizione", punishment). Word and base frequency affected latencies only for deverbal nouns, while an effect of word length emerged for denominal nouns and an inhibitory effect of suffix length was found for both types of stimuli. A high base frequency and a high whole-word frequency both led to higher levels of accuracy. Verb bases led to higher error rates than noun bases. Poor readers, although slower and less accurate than good readers, showed a pattern of results similar to that of typically developing readers. Data confirm that in 4th and 5th graders morphological decomposition may affect reading aloud of long complex words, and that the grammatical class of the base can modulate this effect.