The purpose of this study is to investigate the application of sample entropy (SampEn) measures (Richman and Moorman, 2000) to electrophysiological studies of single and dual tasking performance. It has been proposed that cognitive control mechanisms are required to orchestrate performance of more than one task at a time. If this is the case then it is expected that the entropy values should be changed in the multiple task condition compared with the single task condition. The subjects were 13 healthy individuals from the general population both males and females, aged between 18 and 45 years. Each participant took part in all three of the tasks (auditory task and motor tasks 1 and 2). Brain potentials were recorded using a Scan electrophysiological acquisition system (EAS) (Neuroscan Medical Systems, Virginia, USA). All channels were amplified with a gain of ×150 and bandpass filters of 0.01−100Hz were employed. The signals were digitized using a 16-bit analogue-to-digital converter and sampled at 500Hz. The complexity and regularity of short-duration (~s) epochs of averaged, stimulus-locked electroencephalographic data were analysed using SampEn along with the method of surrogate data. Signals were collected under single and dual tasking conditions. Individual tasks consisted of an auditory discrimination task and two motor tasks of varying difficulty. Dual task conditions were combinations of one auditory and one motor task. Data, mean ± SEM, were compared using the Students t−test with significance taken at P∠0.05. Local ethical approval was obtained for the study. For rare tone stimuli in the single auditory task and the dual auditory and motor task 1, the entropy values for all electrodes in the auditory single task condition were significantly higher than those for the auditory dual task condition (P ∠ 0.05 − 0.001). Comparisons between data for rare auditory stimuli of the single auditory task and the dual auditory and motor task 2 shown that, entropy measurements were significantly higher for single task compared with dual task performance (P ∠ 0.05 − 0.001) for all recorded electrodes. In conclusion, the findings of this study have demonstrated that use of entropy measurements, such as sample entropy, could be alternative nonlinear approaches for analyzing event−related brain potential signals using short term time series. The methods show further promise as a quantitative measure of nonlinear dynamic systems behavior in relation to psychological changes, such as transitions between single and dual task challenges, situations for which the validity of traditional nonlinear dynamical approaches such as estimations of correlation dimension and Lyapunov exponents has recently been challenged.