This article reviews research on speech and language abilities in persons with cri du chat syndrome (CCS). CCS is a rare genetic disorder resulting from a deletion of genetic material on the short arm of chromosome 5 with an estimated incidence between 1 in 15 000 births and 1 in 50 000 births. In general, individuals suffering from CCS have delayed speech and language development, and not all of them develop spoken language at all. Their receptive language has been found to be better than their expressive language, even though both are delayed. In the domain of phonetics and phonology, substitutions, omissions, and distortions are frequent, consonant inventories are small, syllable shapes are restricted, and vowels are variable and overlap with each other acoustically. Persons with CCS have been found to inflect words from all major word classes. Little is known about syntactic skills, but some individuals are reported to express themselves in utterances of two or more words. In spite of these findings, knowlegde about speech and language development in CCS is sparse, and the need for more research is considerable.