In situ side-to-side (STS) anastomosis is a unique technique used for intracranial artery-intracranial artery revascularization. Over a 7-year period, 7 STS anastomoses were performed for anterior cerebral artery aneurysms in 6 patients and a posteroinferior cerebellar artery aneurysm in 1 patient. We provide a step-by-step guide for suturing techniques from arteriotomy to vessel wall sutures based on clinical experiences, with detailed illustrations. Technical considerations in each stage are also discussed. The current technique provides a viable option for treatment of complex aneurysms. ¹⁾