Several studies have noted modest interrater reliability of clinical electroencephalogram (EEG) interpretations. Moreover, no study to date has investigated a means to improve the observed interrater agreement. The purpose of the present study was to examine (i) the interrater reliability of EEG interpretations among three raters (two psychiatrists and one pediatrician); and (ii) how to improve the reliability by establishing a consensus guideline for EEGinterpretation. Three raters, two psychiatrists and a pediatrician, interpreted 100 consecutive EEG recorded at Tajimi General Hospital. After discussing the results of the first trial, the raters established a consensus guideline for EEG interpretation. They then interpreted 50 consecutive EEG recorded at Nagoya City University Hospital following this guideline. Kappa for global judgment of EEG abnormality in three grades (abnormal/borderline/normal) was 0.42 on the first and 0.63 on the second trial. Kappa significantly improved by using the guideline (P = 0.004). It is suggested that discussing and establishing the consensus guideline among the raters offers a feasible method to improve interrater reliability in clinical EEG interpretations.