The study examined the role of sign language and fingerspelling in the development of the reading and writing skills of deaf children and youth. Twenty-six deaf participants (13 children, 13 adolescents), whose first language was Chilean Sign Language (CHSL), were examined. Their dactylic abilities were evaluated with tasks involving the reading and writing of dactylic and orthographic codes. The study included three experiments: (a) the identification of Chilean signs and fingerspelled words, (b) the matching of fingerspelled words with commercial logos, and (c) the decoding of fingerspelled words and the mapping of these words onto the writing system. The results provide convergent evidence that the use of fingerspelling and sign language is related to orthographic skills. It is concluded that fingerspelling can facilitate the internal representation of words and serve as a supporting mechanism for reading acquisition. (Contains 6 figures.)