This paper describes the relevant anatomy and rationale behind our Diffusion Technique for intercostal nerve block. Using the Diffusion Technique developed by Omoigui, the left middle and index fingers are placed to stabilize the superior and inferior borders of the rib, at a site proximal to the area of pain. A 3 cm, 25 gauge, short-beveled needle is inserted directly onto the midpoint of the rib and 1-3 ml of local anesthetic solution is injected over the rib. There is no attempt to walk off the lower border of the rib and there is no advancement of the needle into the subcostal groove. There is minimal to no risk of any accidental pleural puncture as compared with the Bonica technique. The Omoigui diffusion technique utilizes the spread and diffusion characteristics of the injected local anesthetic to produce blockade of the cutaneous branches and intercostal nerves. This diffusion technique has showed similar therapeutic results as the standard approach. We include a series of cases that responded successfully to this simple diffusion technique for intercostal nerve block.