This paper concerns the practical measurement of vigilance in a working environment. Vigilance can be measured in a number of ways, of which the electroencephalogram (EEG) is probably the most popular. However, the EEG method is not practical in a dynamic work setting for a number of reasons. This paper introduces a technique for assessing vigilance by means of easy-to-use and sensitive objective (performance) and subjective (questionnaire) behavioral measures. This technique does not include predefined or specified tasks, but a general principle of assessment. Vigilance assessment can be achieved by administering a vigilance test battery that includes a short working memory task and a short questionnaire. In situations that do not allow presentation of test batteries, both vigilance and the degree of (under-) stimulation can be assessed by performance on work-embedded tasks. This, however, requires analysis of the task set for a given job. It is discussed with what parameters a measurement technique needs to be described in order to determine exactly which measure(s) to use in a particular situation.