Question: Deliberation is the process of weighing alternatives. The aim of this study was to investigate neuronal correlates of a deliberation process leading to a motor decision. Methods: In this study 23 young right-handed subjects (age: 18 – 27, 12 female) had to press a key with either the right or left hand, depending on a visual stimulus. The stimulus consisted of a word indicating a colour written either in the corresponding colour (e.g. word “red” written in red : match condition) or written in a different colour (mismatch condition). Subjects had to decide between responding with the right hand in the match condition, or with the left hand in the mismatch condition. High-density multi-channel EEG activity was recorded as well as behavioural data. In addition reaction times of the deliberation tasks were compared with those of a corresponding simple motor task. Results: The reaction time in the deliberation task was significantly different from that observed during the simple motor task. Moreover, within the deliberation task the reaction times for the mismatch condition are significantly longer than those for the match condition. The EEG patterns recorded from above the motor cortices during both tasks show clear differences. During the simple motor task a typical pre-motor positivity is observed preceding the key press whereas during the deliberation task a strong negativity approximately 300 ms before movement onset is found. Subtracting the motor task pattern from the EEG pattern of the deliberation task augments the preceding negativity, presumably implying a required cognitive process. Conclusions: The deliberation process during movement decision is represented by an increasing negativity in the motor region before movement onset. As both hemispheres show a similar activation it is assumed that competing motor plans are processed simultaneously. This result supports the idea for an involvement of the motor cortices in the deliberation process.