Background: Growing evidence encourages the preventive role of vitamin D in pancreatic carcinoma (PC). Meanwhile, the prognostic or predictive role needs more investigations. This study aimed to evaluate the correlation between serum vitamin D levels and the clinicopathological features with the outcome in advanced pancreatic carcinoma (APC). Materials and methods: The current prospective study included 176 patients with APC. Assessing 25-hydroxy vitamin D is the most accurate method to measure the serum vitamin D levels. Serum vitamin D levels <20 ng/ml are defined as vitamin D deficiency, while levels ranging from 20 to 29 ng/ml are defined as vitamin D insufficiency. Before any treatment modalities were administered, the serum vitamin D levels were measured by enzyme-linked immunosorbent assay (ELISA). Results: Serum vitamin D insufficiency and deficiency were detected in 28.4% and 31.8%, respectively. A large tumor size, higher grade, liver metastasis, higher serum level of CA 19-9, poor ECOG PS, and low overall response rate (ORR) were associated with lower serum vitamin D levels (p = 0.000). The median follow-up period was 7.6 months (range 0.6–18.6). The ORR was 23.2%, 54%, and 82.9% of vitamin D deficiency, insufficiency, and normal levels of vitamin D, respectively. The median OS was 11.4 months for patients with normal serum vitamin D levels, compared with 2.7 and 7.03 months for serum vitamin D deficiency and insufficiency, respectively. Conclusion: Among patients with APC, serum vitamin D levels are considered a promising prognostic factor. It is associated with various poor prognostic features and worse survival outcome.