Tuberous sclerosis complex is a disease that affects many organs, including the central nervous system. Nervous system involvement in the form of hamartomas often results in seizures. In this study we wanted to determine the outcome of epilepsy in tuberous sclerosis complex and determine whether interictal electroencephalograms (EEGs) and hamartoma burden as seen with magnetic resonance imaging (MRI) are predictive of degree of seizure control. The study population consisted of 30 patients. For each patient two sets of EEG and MRI data, separated by at least 12 months, and information on seizure frequency at time of data collection were obtained. Sensitivity, specificity, and positive and negative predictive values of various EEG and MRI findings were determined. Seizure control improved in 20 and worsened in 10 patients. In relation to seizure control, the specificity of an abnormal sleep EEG and the positive predictive value of normal sleep EEG were 100%. MRI and EEG background were neither sensitive nor specific for predicting seizure control. A majority of children with tuberous sclerosis complex can achieve good seizure control. The sleep EEG is helpful in predicting eventual seizure control.