Introduction Workers’ mental health should be valued since the causes of work abandonment due to problems related to mental health already occupy the first position in the statistics in some countries. Knowledge about the means of measuring the mental load in the work environment can help the occupational health team to identify causes of absence, propose ways of prevention, seeking a better adaptation of the work cycle to the worker. The comprehension of the measurement methods available in the literature also helps to guide the choice of the most appropriate scale according to the type of demand to be applied.

Methods Literature review about the forms of evaluation of mental workload, carried out between June and November of 2016, using the following descriptors combined: ‘occupational mental load’, ‘Mental work load’, and ‘NASA-TLX’ at SciELO, Lilacs and Medline databases.

Result A total of 34 articles were selected, of which 80% used the NASA-TLX scale as a method of analysis or as a comparison for validation of new scales.

Discussion The mental workload scales should be selected according to what is prioritised in the research results. In addition, variability may occur in the application of the same scale with different populations; which corroborates with the definition that the mental load has factors that are specific to the individual and his sociocultural environment. Thus, external and personal factors may interfere in different ways in the assessment of mental load expenditures according to the task.