Ictal alterations of the level of general awareness and subjective content of consciousness play a pivotal role in the clinical phenomenology of epilepsy, and reflect the pathological involvement of different neurobiological substrates. However, no self-reported measures have been proposed for patients experiencing altered conscious states during seizures. This study describes the development and validation of a new scale for the quantitative assessment of the level and content of ictal consciousness, the Ictal Consciousness Inventory (ICI). The ICI is a 20-item questionnaire generated on the basis of interviews with patients, literature review, and consultation with experts. It was tested on a sample of 110 patients attending three different epilepsy clinics in Northern Italy, who also completed standardized clinical scales. Standard psychometric methods were used to demonstrate that this scale satisfies criteria for acceptability, reliability, and validity. The ICI is proposed as a user-friendly and clinically sound instrument for the measurement of ictal alterations of consciousness in patients with epilepsy.