Objective: Recognizing delirium phenomenology (DP) aids the early diagnosis of this syndrome and improves quality of life in patients with advanced cancer. The aim of this study was to identify the neurobehavioral and cognitive patterns of delirium-related symptoms in persons with advanced cancer. Methods: We conducted an observational comparative prospective study on delirium in patients with advanced cancer in different palliative care settings, assessing the presentation/evolution of DP with the Memorial delirium assessment scale (MDAS). Results: Two hundred twenty-seven patients were enrolled on hospital/hospice admission. Of these, 57 were admitted with delirium, 170 without delirium, and 31 developed delirium during hospitalization. Of the 88 patients admitted with delirium or who developed it during hospitalization, only 32 underwent two consecutive MDAS evaluations (at diagnosis and after one week). Delirium resolved in 22 patients (first average MDAS score 10.08 vs. second 3.6 [p < 0.001]). Disorientation, short-term memory, and memory span were altered in all patients with unresolved delirium. The same features were altered in 18 (80%), 17 (80%), and 16 (70%) of the patients with resolved delirium, respectively, and in 58 (35%), 114 (67%), and 38 (23%) of no-delirium patients, respectively. Conclusion: Cognitive-related symptoms appear to be the most prevalent and earliest signs of DP in patients with advanced cancer.