Post-stroke delirium (PSD) after intracerebral hemorrhage (ICH) is considered to be even more detrimental compared to that after ischemic stroke. Treatment options for post-ICH PSD remain limited. This study aimed at investigating to what extent prophylactic melatonin administration may have beneficial effects on post-ICH PSD. We performed a mono-centric, non-randomized, non-blinded, prospective cohort study, including 339 consecutive ICH patients admitted to the Stroke Unit (SU) from December 2015 to December 2020. The cohort consisted of ICH patients who underwent standard care (defined as the control group) and ICH patients who additionally received prophylactic melatonin (2 mg per day, at night) within 24 h of ICH onset until the discharge from the SU. The primary endpoint was post-ICH PSD prevalence. The secondary endpoints were: (i) PSD duration and (ii) the duration of SU stay. The PSD prevalence was higher in the melatonin treated cohort compared to the propensity score-matched (PSM) control group. Post-ICH PSD patients receiving melatonin had shorter SU-stay durations, and shorter PSD durations, although not statistically significant. This study shows no efficacy in limiting post-ICH PSD with preventive melatonin administration.