Objective: To determine the availability, accessibility, and affordability of EEG, EMG, CSF analysis, head CT, and brain MRI for neurologic disorders across countries.Methods: An online, 60-question survey was distributed to neurology practitioners in 2014 to assess the presence, wait time, and cost of each test in private and public health sectors. Data were stratified by World Bank country income group. Affordability was calculated with reference to the World Health Organization's definition of catastrophic health expenditure as health-related out-of-pocket expenditure of .40% of disposable household income, and assessment of providers' perceptions of affordability to the patient.Results: Availability of EEG and EMG is correlated with higher World Bank income group (correlation coefficient 0.38, test for trend p 5 0.046; 0.376, p 5 0.043); CSF, CT, and MRI did not show statistically significant associations with income groups. Patients in public systems wait longer for neurodiagnostic tests, especially MRI, EEG, and urgent CT (p , 0.0001). The mean cost per test, across all tests, was lower in the public vs private sector (US $55.25 vs $214.62, p , 0.001). Each drop in World Bank income group is associated with a 29% decrease in the estimated share of the population who can afford a given test (95% confidence interval 233.4, 25.2; p , 0.001). In most low-income countries surveyed, only the top 10% or 20% of the population was able to afford tests below catastrophic levels. In surveyed lower-middleincome countries, .40% of the population, on average, could not afford neurodiagnostic tests. It has been argued that diagnostic tests for neurologic disorders are difficult to access in many countries, especially in countries of lower income status; however, few actual data are present to support this concern. Particularly, little information is available for low-and middle-income countries (LMICs) where neurologists are generally rare, if not completely absent. Conclusions:1,2 Even where human resources and technology are available, it is not clear what proportion of the population has access to neurodiagnostic testing given the generally uneven distribution of health resources in LMICs. 3One study 4 including 44 African countries in 2001 focused on neurosurgical resources and found that 18 countries had no CT scanners, 13 countries had only one CT scanner each, and only 13 countries had more than 2 CT scanners each. Similar data on EEG, EMG, MRI, and CSF studies are not available. Given the lack of collected knowledge on neurologic testing, particularly in LMICs, we conducted a survey of physician respondents engaged in the practice of neurology worldwide. The objective of the present study was to assess the availability, accessibility, and affordability of neurodiagnostic tests across low-, middle-, and high-income countries.