Background: Successful reading can be achieved by means of two different procedures: sub-word processes for the pronunciation of words without semantics or pseudowords (PW) and whole-word processes that recruit word-specific information regarding the pronunciation of words with atypical orthography-to-phonology mappings (exception words, EW). Methods: We compared reading abilities between 35 young and 35 older adults in an experimental reading task including low-frequency regular (RW), EW and PW. Results: A significant effect of word type, group and an interaction word type by group was found for errors. Young adults made significantly more regularization errors than older subjects for EWs. Conversely, young readers read PW and RW significantly faster. These results indicate that older adults compared with younger adults are more accurate when reading low-frequency EW. Conclusion: The fact that young adults were faster than the elderly for PW and RW reading, together with a larger number of regularization errors in EW reading, suggests that they relied on sub-word processes to a larger extent than the older group.