Aim. The primary aim of the research was to define the relation between semantic satiation effect, overactivation of semantic network and a symptom of derealisation in people suffering from schizophrenia. The semantic satiation was defined as the subjective and temporary experience of loss of meaning of repeatedly pronounced words or images which is the result of excessive activation in the semantic network. Because overactivation in semantic network is common feature of schizophrenia, it was expected that schizophrenic patients would be prone to satiation effect more than healthy subjects. Methods. Satiation of negative, positive and emotionally neutral images was determined for patients suffering from schizophrenia and in healthy controls. The subjects were presented with pictures from different categories flashed on a computer screen 3, 13, 23 and 33 times. Each presentation was followed by the category name and the subjects decided, whether the object presented on the photograph belonged to this category. It was expected that the loss of meaning of satiated images would delay participants' lexical decision and that this effect should be stronger for the schizophrenic than for the control group. Results. Reaction times to a decision based on repeated images were longer in a group of patients suffering from schizophrenia than in the control group. It was also observed that in the group of patients the satiation effect depends on valence of satiated images. Emotionally positive and negative pictures were satiated faster than neutral ones. Discussion. The conducted experiment confirmed the greater susceptibility of patients to the effect of semantic satiation. It has been revealed that subjective experience of the loss of meaning of images depends on the valence of stimuli.