We investigate whether retrograde-amnesia can be indexed with pupil activity. We present the case of L, 19-year-old, without neurological or psychiatric disorders except for retrograde-amnesia. We invited L to retrieve retrograde and anterograde memories while his pupil size was monitering with eye-tracking glasses. Results demonstrated impaired retrograde retrieval but successful anterograde retrieval in L. He also attributed lower emotional value and visual imagery to his retrograde compared to his anterograde memories. Critically, smaller pupils were observed during retrograde than during anterograde retrieval. Our study provides the first evidence on the value of pupillometry as a potential physiological marker of amnesia.