To assess meningitis treatment in Lebanon's compatibility with the Infectious Diseases Society of America (IDSA) guidelines and the effect of non-compliance on mortality. Methods: This is a retrospective study, conducted in 5 Lebanese hospitals, and enrolling all patients diagnosed with meningitis who presented to the involved hospitals from January 2008 to December 2016. Results: A total of 252 participants were enrolled in the study. Of these patients, 205 (82.7%) were diagnosed with viral meningitis and 47 (17.3%) with bacterial meningitis, which was confirmed using laboratory tests. For patients with viral meningitis, 128 (62.4%) remained on the initial prescribed antibiotics despite the negative cerebrospinal fluid (CSF) and blood culture results. For bacterial meningitis patients, 30.8% received treatment regimen incompatible with the IDSA guidelines. The most common reason for the treatment incompatibility was the definitive drug choice after the culture results (49.1%) and the least common reason was inappropriate hospital stay days (25.9%). The mortality rate was 13.5%. Having low proteins values in the CSF (odds ratio=0.095) was associated with lower mortality compared to patients with normal protein values. Conclusion: This study shows a high percentage of inappropriate treatment in Lebanese hospitals despite these hospitals having adopted international treatment guidelines. This inappropriate management was associated with an increasing rate of mortality and neurological complications.