Background: This study aimed to assess mothers' knowledge regarding multivitamin use for their children in primary health care settings. Methods: It is a cross-sectional survey targeting mothers visiting Primary Health Care. A questionnaire with 14 questions was distributed among two major primary care clinics. Sampling was convenient, and randomness was assumed by visit sequence, on a first-come, first-served basis, and those who agreed to participate. Mothers visiting the Pediatric and Well Baby Clinic within the PHC centers for immunization of their children (under 2 years old) may have been disproportionately selected by this sampling method. The data were entered and analyzed using SPSS with univariate analysis on each question and use of chi-square, exploring mothers' reasons and practices of vitamin use. Results: In our survey, most mothers (62.3%) believed that the best age of giving multivitamins to their children is in the 1st year of life. Twenty-five percent (25%) believed giving at 2 years old is best. Forty-five percent (45%) believed that multivitamins are good for both boys and girls, whereas 33.5% believed that only girls needed it, and 21% believed that only boys need multivitamins. Mothers who believed that children need multivitamins in the first year of life were 2.3 times more likely to give multivitamins to their children than mothers who believed that multivitamins are important after the first year of life. Mothers who believed that their children benefit most from multivitamins in the first year of life were 1.85 times more likely to give them multivitamins to help increase their weight and physical development. Conclusion: Mothers who know foods containing vitamins are 3 times more likely to give multivitamins to their children. In this study, there is no significant difference between the opinions of mothers giving and not giving multivitamins to increase appetite for physical development beyond the first year of life or prevent diseases or for children with chronic illnesses. Others knowledgeable about foods containing multivitamins were similar to mothers who had no knowledge of buying and preparing foods at home.