Brain tumor-related epilepsy is a common complication of primary and metastatic brain tumors with seizures often representing the first manifestation of the tumor. The size and location of the tumor can make detection of epileptiform discharges on scalp electroencephalogram and safe surgical resection challenging. We describe a case of a patient with glioblastoma multiforme presenting as dominant temporal lobe epilepsy. Seizures were manifest as episodes of speech arrest on a background of long-standing history of episodic speech difficulty and headache. In this case, recognizing a change in semiology allowed diagnosis of a high-grade glioma. Use of electrocorticography during surgical excision of the tumor guided safe maximal excision without damage to eloquent cortex and helped confirm the diagnosis of brain tumor-related epilepsy.