Hemorrhagic complications related to bone marrow aspiration and trephine biopsy are uncommon. Risk factors include thrombocytopenia, myeloproliferative disorders, concurrent use of anticoagulants, and obesity. Here we describe our technique for bone marrow aspiration and biopsy of the posterior iliac crest using CT guidance. Our technique ensures needle passage only through subcutaneous fat and bone, avoiding muscle and neurovascular structures, as well as controlled and precise needle advancement within bone. This technique should be considered for use in patients that are at increased risk for procedure related complications, particularly obese patients, where surface anatomical landmarks may prove unreliable.