Flickering light and color patterns, reading, language, movement, decision making, eating, tapping and touching, hot water immersion and auditory stimulation can induce seizures in some epileptic patients. These are known as the "reflex epilepsies". The mechanism of reflex epilepsy is not clear. Recently, we performed anterior two-thirds corpus callosotomies in two reflex epilepsy patients (ages 12 and 14 years), with follow-up for more than three years. Patient 1 had Lennox-Gastaut syndrome with auditory-induced generalized atonic or tonic seizures (startle epilepsy), which decreased by 60% after callosotomy. Patient 2 had Lennox-Gastaut syndrome with somatosensory-induced generalized tonic seizures (tap epilepsy). He was seizure-free for one year immediately after callosotomy, but his seizures recurred with the same degree and frequency as before surgery. The nonsignificant postoperative seizure outcome suggests that the corpus callosum only plays a partial role in seizure generation. Our report also discusses the possible mechanisms of generation of reflex seizures.