Background: The reported incidence of Traumatic Lumbar Puncture (TLP) is variable and is unknown in Chilean Pediatric Hospitals. Objective: To determine the incidence of TLP in Roberto del Río's Pediatric Hospital , and the influence of the age and the location where the procedure was performed. Methods: A retrospective study was conducted including all patients who had Cerebrospinal fluid (LCR) samples sent to the Main Laboratory of the mentioned Institution between 2002 and 2004. The traumatic lumbar puncture was defined by the presence of more than 400 red blood cells by mm 3 . The information of the emergency service attention registry and clinical charts were obtained. Results: Four hundred and twenty two samples were obtained, with an incidence of TLP of 19,43%. Of the total of procedures, 53,1% were performed at the Emergency department and 46,9% in any other location at the hospital, with a calculated incidence of 11,6% and 26,3% respectively (OR=4.0; IC 95%=2,41 a 6,9). The incidence in patients younger than 6 months was 26,1% compared with 14,1% in older (OR= 2,2; IC 95%=1,24 a 3,8). Conclusion: The incidence of traumatic lumbar puncture is 19,43%. The rate of PLT was significantly less in PL performed in the ED compared with any other location at the hospital and was greater in patients younger than 6 months compared with olders.