Abstract: A convenient study was conducted to evaluate vitamin B12 status among young healthy adult Jordanians and to check for the true vitamin B12 deficiency. One hundred sixty five subjects were recruited in the study. The subjects were chosen to be healthy aged between 20-40 years. Participants were asked to fill a detailed questionnaire that covers social and medical data as well as data on frequency consumption of food sources of vitamin B12. Blood tests including CBC, blood film and serum vitamin B12 level were done for all volunteers. For those with serum B12 <300 pg/ml, plasma Methylmalonic Acid (MMA) was measured to confirm deficiency. Results showed that 27.3% had vitamin B12 deficiency according to standard B12 deficiency definition (<200 pg/ml), 41.8% had serum B12 between 201-300 pg/ml and 30.9% had normal B12 levels (>300 pg/ml). Among those with B12 <300 pg/ml, 47.4% had confirmed deficiency, using MMA as an indicator. Even, 44.9% of those with serum B12 between 201-300 pg/ml had confirmed B12 deficiency. Vitamin B12 status was found to be positively correlated with age, but negatively correlated with MCV. No significant associations were found between B12 status and gender, BMI, household size and total vitamin B12 intake. It is concluded that serum B12 level is not a specific test for true vitamin B12 deficiency. Furthermore, dietary vitamin B12 intake by itself is not an indicator of B12 deficiency.