In this study, the language-related ERP studies relevant to the functionalrole of the N400 and P600 in semantically anomalous sentences andthe underlying reasons which may affect their functions were reviewed.Since their discovery, the N400 and P600 have been the most importantlanguage-related ERP components. The N400 has been mostly elicited asa result of processing sentences with lexical and semantic anomalies, butlater on, in many studies instead of the expected lexical-semantic N400effect, semantic anomalies elicited a P600 effect called semantic P600.However, the functional interpretation of these two ERP componentshas constantly been a matter of debate. Perhaps most notably, it isproposed that it is not just the N400 which is related to semanticanomalies but the P600 can also be reflected as a result of these kindsof anomalies. Reviewing the literature for explaining the functions of thetwo ERP components, the N400 and the P600, during the processingof semantic anomalies revealed that still there is a need for moreresearch on language processing in order to make the researcherscapable of describing the underlying factors influencing them,especially more focused investigations of the functional-anatomicaland neurocomputational models may provide a clearer understandingof them. Moreover, any practical theory or model of the N400 andthe P600 in language comprehension needs to consider the apparentinconsistencies in the elicitation pattern of the N400 and the P600 inorder to successfully capture the full data spectrum.