To summarize the current evidence on the diagnostic evaluation of cranial cerebrospinal fluid (CSF) leaks and encephaloceles, including laboratory testing and imaging studies.The most sensitive and specific laboratory tests for CSF leak diagnosis are beta-2-transferrin and beta trace protein assays, the former more commonly used because of availability. Imaging studies used for localization of the leak site include high resolution computed tomography (HRCT) and magnetic resonance cisternography (MRC), often used in combination. Intrathecal contrast administration is reserved for complex cases with prior equivocal test results or for patients with multiple skull base defects to localize the leak site.Diagnosis of CSF leaks and encephaloceles is aimed at both confirming the leak and localizing the leak site. Future advancements in testing techniques may shorten the diagnostic process, limit the need for invasive testing, and improve the safety of such testing in indicated cases.