We describe a study of syntactic intervention administered to a 12;2-year-old individual with syntactic SLI, who had difficulties in the comprehension and production of structures containing syntactic movement such as relative clauses, object questions, topicalization sentences, and sentences with verb movement. The intervention, comprised of 16 sessions, was based on syntactic theory and included explicit teaching of syntactic movement, relying on a type of syntactic knowledge that was intact ĝ€" the argument structure of the verb. The participant's performance was assessed before and after treatment, and for some of the tests also during the treatment and 10 months later. The performance was assessed using various tasks that targeted comprehension, repetition and elicitation of semantically reversible sentences. Following treatment, the participant's performance on all structures with syntactic movement showed substantial improvement compared with baseline, in many of the tasks reaching the performance of the age-matched control group. Treatment of phrasal movement resulted not only in improvement in treated structures, but also in generalization to untrained structures: although phrasal movement was only treated directly for relative clauses and topicalization structures, the comprehension of object Wh-questions, which also include phrasal movement, improved as well. The high performance level was maintained 10 months after the treatment.