Bone marrow aspiration (BMA) is increasingly being used to harvest stem cells for use in regenerative medicine. The focus of BMA in interventional orthopedics is to maximize the yield of mesenchymal stem cells. The authors present an improved method for BMA that involves fluoroscope or ultrasound guidance combined with anesthesia; in the authors’ experience, it produces the highest possible stem cell yield and is well tolerated by patients. The authors provide a step-by-step guide to the process, along with a discussion of technical and other considerations and quick reference guides for ultrasound- and fluoroscope-guided BMA.