ABSTRACT:EEG recordings may contain a variety of artifacts. Identification and understanding of these artifacts is essential for accurate interpretation of the EEG. Physiologic artifacts that may be seen in EEG include respiration-related artifact. We report the occurrence of a highly unusual respiration-related artifact that consisted of bursts of rhythmic, intermittent, high-amplitude theta activity. Its relationship to the respiration was identified and appropriate intervention (suction of nasal respiratory passage and repositioning of head) led to resolution of the artifact. The artifact was unusual in morphology and unusual in the way in which it was caused by the respiration.