In the afternoon of March 11, 2011, Kesennuma City was hit by the Great East-Japan Earthquake and a devastating tsunami. The purpose of this retrospective study is to document possible changes in the number of patients with distinct neurologic diseases seeking treatment following this disaster. Because of Kesennuma's unique geographical location, the city was isolated by the disaster, allowing for a study with relatively limited population selection bias. Patients admitted for neurologic emergencies from January 14 to May 5 in 2011 (n = 117) were compared with patients in the corresponding 16-week periods in 2008–2010 (n = 323). The number of patients with unprovoked seizures was significantly higher during the 8-week period after the earthquake (n = 13) than during the same periods in 2008 (n = 6), 2009 (n = 3), and 2010 (no patients) (p = 0.0062). In contrast, the number of patients treated for other neurologic diseases such as stroke, trauma, and tumors remained unchanged. To our knowledge, this is the first report of an increase in the number of patients with seizures following a life-threatening natural disaster. We suggest that stress associated with life-threatening situations may enhance seizure generation.