Background: An arteriovenous malformation is a collection of dysplsatic plexiform vessels that is supplied by one or more arterial feeders and drained by one or more venous channels. Arteriovenous malformations may have a pure plexiform nidus or contain a mixed plexiform fistulous nidus. Objective: This work was carried out to evaluate the clinical outcome and effectiveness of the endovascular treatment of cerebral arteriovenous malformations with ethylene vinyl alcohol copolymer (Onyx). Methods: Twenty five patients (14 males and 11 females) with cerebral arteriovenous malformations were treated by embolization with Onyx at the Neurointervention Unit in Al-Azhar University. All patients with intracranial AVMs were subjected to preprocedural, procedural and postprocedural assessments. Result(s): There was significant difference in nidus diameter in all patients after embolization in comparison to before embolization. There was significant difference in Spetzler and Martin grading system before and after embolization. Conclusion(s): Onyx as a new embolic material, with its non-adherent properties has significantly facilitated this development.