The impact of needle size on the frequency of post-lumbar puncture syndrome (PPS) was investigated in 77 patients undergoing diagnostic lumbar puncture. 22-gauge needles were used in 44 patients (group A) and 19-gauge needles in 33 (group B). Because of severe postdural headache, an epidural blood patch was applied in 6 patients and resulted in immediate relief of symptoms. In the remaining 71 patients, PPS occurred in 57% of group A and in 48% of group B. A statistically significant relationship could not be found between needle size and duration of PPS (p = 0.2), but an inverse ratio was found between age and duration of post-lumbar puncture headache (p = 0.006). A review of previous studies in this field shows that needles with a diameter smaller than 24 gauge reduce the incidence of PPS. However, technical skill is also of prime importance in lowering the frequency of postdural headache.