Background: In our laboratory, we received many cases of Vitamin B12 deficiency without anemia, and we observed that the deficiency is more prominent in females than males. It is well known that Vitamin B12 deficiency is usually associated with macrocytic anemia. However, the clinical importance of Vitamin B12 insufficiency without any hematological abnormality is underestimated in the Sulaymaniyah city population. Thus, the aim of this study is to assess the frequency of Vitamin B12 deficiency with normal complete blood counts (CBCs), especially in the middle- and old-aged population. Materials and Methods: Within the period from April 2018 to April 2019, the patients came to the Dr. Hisham Alrawi Private Laboratory for Vitamin B12 level estimation; the CBCs for all patients with Vitamin B12 deficiency have been collected. We selected patients with low-level Vitamin B12, which were 149 patients, aged 30 years and above. Normal serum Vitamin B12 value in our laboratory is 191–633 pg/ml according to the e411 Roche competitive-binding luminescence immunoassay system. CBC has been collected were done for all patients with Vitamin B12 deficiency by Orphee Mythic 18 Hematology Analyzer. Results: The mean of their age is 64 years, and the mean of hemoglobin (Hb) level is 12.1 g/dL, whereas the mean of Vitamin B12 level is 131.3 pg/ml. About 74 (49.6%) of them have anemia, and 75 (51.4%) are with the normal CBC parameters. The mean of the Hb in females is with the normal range (12.1 g/dL), whereas the mean of the Hb in the males is lower than the normal range (12 g/dL). Conclusions: Vitamin B12 deficiency is common in middle and old age in Sulaymaniyah city, especially in females. Thus, screening programs for B12 levels estimation for this age group are recommended to avoid expected complications.