The iliac bone crest is one of the most valuable regions for harvesting bone grafts, both vascularized and nonvascularized. Since the first commendable description of this region as a possible source for vascularized bone flaps by Taylor, little relevant information concerning the variations of the deep circumflex iliac vessels and their relationship to the neighboring structures has been published. The purpose of the current study was to examine this region clinically and anatomically, taking into consideration the former description by Taylor. We gathered all our findings on 216 iliac regions and proposed a new classification. In addition we measured the relationships between the deep circumflex iliac artery and important surgical landmarks. A comparison of our finding with other studies showed similarities and differences but was far more complete. Generally (92%) the deep circumflex iliac artery (DCIA) originated from external iliac artery (EIA) behind the inguinal ligament (IL) and passed cranio-laterally toward the anterior superior iliac spine, where it divided into two important branches. Four variations were observed of the DCIA. The deep circumflex iliac vein (DCIV) ran over (82.5%) or under (17.5%) the EIA. The superficial circumflex iliac vein (SCIV) was observed draining into the DCIV in some dissections. Three different variations of the superficial circumflex iliac artery (SCIA) were observed. The anatomical knowledge of these variations and their correlation to important surgical landmarks can help in harvesting the DCIA flap more safely and thus increasing the success rate while reducing donor site morbidity. Clin. Anat., 2013. © 2013 Wiley Periodicals, Inc.