Introduction: Vitamin B12 deficiency is a common condition in the geriatric population, especially in people over 60 years of age. This vitamin is essential for key functions such as red blood cell formation, DNA synthesis and maintenance of the central nervous system. Decreased vitamin B12 absorption in the elderly may be due to a variety of factors, such as gastric atrophy, the use of certain medications, and chronic diseases that affect intestinal absorption. In addition, inadequate dietary habits and certain sociodemographic factors, such as advanced age, educational level, and marital status, also play an important role in the prevalence of this deficiency. Objective: To investigate the prevalence of vitamin b12 deficiency and associated factors in geriatric outpatients of the Essalud III Iquitos Hospital, 2023 2024. Methods: An observational type of study with a cross-sectional and...