A new generation of Atraumatic (blunt tipped) needles now exists in addition to the traditional Quincke (cutting tip) needles for LP. We wished to identify the optimal size and type of needle that should be used for this technique. Requirements include rapid and accurate transduction of CSF pressure and adequate flow rate for CSF collection purposes while minimizing headache and other neurologic sequelae. Different types of available Atraumatic and Quincke needles were tested in two models that simulated normal and raised CSF pressures. The flow rates and the time required for an accurate transduction of CSF pressure onto a standard spinal manometer through each needle type was measured. Overall, Atraumatic-tipped needles compared favorably with similarly sized Quincke needles tested. The 20-gauge needles displayed suitable flow and pressure transduction characteristics. Some of the 22-gauge Atraumatic needles rapidly measured CSF pressure, but their flow rates were only suitable for small volume CSF collection. There is extensive literature to support that neurologic sequelae are reduced using Atraumatic needles. Diagnostic LP can be easily and accurately performed by using a large Atraumatic needle with the potential for considerable reduction in post-LP headache and related neurologic sequelae.