##1. General vegetarians (Non-vegans) For non-vegans, dairy products seems to be the best source, as mentioned in other answers as well. [List of top 4 (I'm excluding eggs)][2]: > #1: Cheese > The amount of vitamin B12 in cheese depends on type and variety, Swiss cheese provides the most with 3.34μg per 100g serving > (56% DV), followed by Gjetost(40% DV), Mozzarella(39% DV), Tilsit(35% > DV), and Feta(28% DV). > > #2: Whey Powder > Once thought the sole domain of body builders, whey powder is now entering main stream as more people are going > vegetarian. Whey powder is a common addition to breads and smoothies, > 100 grams will provide 2.5 μg of vitamin B12 or 42% of the DV. > > #3: Milk and Yogurt > 100 grams of non-fat yogurt provides 0.53μg (10% DV) of vitamin B12 and 15%DV per cup. 100 grams of reduced fat milk > provides 0.46μg (8% DV) and 19% DV per cup. > > #4: Yeast extract Spreads (Marmite) > Yeast extract spreads are popular in Britain and Europe, and have started to gain popularity in the U.S. > A good vegetarian source of protein, the spread also packs a lot of > vitamin B12. One hundred grams provides 0.5μg (8% DV) of vitamin B12, > that is 0.03μg (1% DV) per teaspoon. ##2. Vegans As a vegan, I personally rely on nutritional yeast and multivitamins. There are some [important points][1] which are worth learning more about: > ###Is B12 Vegan? > > The vitamin B12 component in B12 supplements and fortified foods is > made by bacteria and sourced from bacteria cultures; it is not taken > from animal products. However, some companies might put gelatin in > their B12 supplements, though this appears to be less and less common. > It is easy to find vegan B12 supplements on the Internet or in grocery > stores in developed countries. > > There are some live food supplement companies that rely on spirulina > or other algae, rather than bacteria cultures, as a source of vitamin > B12. You should not rely on such products for your vitamin B12 as > testing has indicated it is not a reliable source of active vitamin > B12 (more information). > > Streptomyces griseus, a bacterium once thought to be a yeast, was the > commercial source of vitamin B12 for many years (8, 9). The bacteria > Propionibacterium shermanii and Pseudomonas denitrificans have now > replaced S. griseus (10). At least one company, Rhone Poulenc > Biochimie of France, is using a genetically engineered microorganism > to produce B12 (11). > > ###Fortified Foods > > There are many vegan foods fortified with B12. They include non-dairy > milks, meat substitutes, breakfast cereals, and one type of > nutritional yeast. > > The "Daily Value" for B12 found on food labels is based on 6 µg, which > was the RDA in 1968. If a label says a food has, for example, 25% of > the Daily Value of B12, it has 1.5 µg (25% of 6 µg = 1.5 µg). > > ###Brewer's and Nutritional Yeasts > > Brewer's and nutritional yeasts do not contain B12 unless they are > fortified with it. There is at least one vegan, B12-fortified yeast > currently on the market: Red Star Vegetarian Support Formula. > (Twinlab's SuperRich Yeast Plus contains whey). > > ###Cooking > > Tucker et al. (2000, USA, 13) found that vitamin B12 from fortified > breakfast cereals and dairy products was associated with better > vitamin B12 status than was B12 intake from red meat, poultry, and > fish, leading the researchers to suspect that the B12 from meat might > be damaged by cooking. The B12 in animal foods tends not to be > cyanocobalamin, the form used in fortified foods and that is more > stable during cooking. For example, in an acid medium (pH 4-7), > cyanocobalamin can withstand boiling at 120° C (1). > > Even so, for people wondering whether they are destroying the B12 in > their fortified foods by cooking, we do not have enough evidence to > know for certain, so it is safest to make sure you rely on uncooked > sources of vitamin B12. [1]: http://www.veganhealth.org/b12/vegansources [2]: https://www.healthaliciousness.com/articles/Top-5-Natural-Vegetarian-sources-Vitamin-B12.php