The literature on grammatical skills in persons with Cri du chat syndrome (CCS) is very limited, and the need for more knowledge in this area is thus evident, in particular for speech and language therapists working with individuals with this syndrome. This case study report describes the syntactic skills of a 14-year-old Norwegian girl with CCS. The theoretical framework is construction grammar. Data for the study were collected in a diary by the author over a period of 4 months and make up a corpus of 552 utterances. These utterances are described in terms of MLU, diversity of argument structure constructions, proportion and types of complex utterances, use of auxiliaries, as well as deviant word order patterns, types of omissions, and use of prefabricated units. The primary aim of the study is to identify strengths and weaknesses in syntactic skills, which provide the basis for future research on grammatical skills in persons with CCS. (Contains 3 figures, 1 table and 5 notes.)