The problem of consciousness has become important in many recent works on the cognitive neurosciences and has always been present in the description of the disorders resulting from brain lesions. In this article, the modifications of the states and contents of consciousness are examined in relation to the cognitive disorders resulting from brain lesions. Disorders of consciousness are observed in anosognosia and when the subject is confronted with simultaneously occurring, incoherent or contradictory interpretations of the world or of his own actions. It is suggested that normal subjects are usually only aware of the result of their cognitive processes. In neuropsychology some disorders of consciousness can be interpreted either as lack of monitoring of the ongoing processes (anosognosia) or as reflecting the existence of contradictions between results of different processing components in a cognitive architecture (which result in fragmented conscious experiences). Consciousness is also discussed in reference to goal-oriented behavior and dysexecutive functions as well as in relation to the functioning and the nature of episodic and autobiographical memory.