Calcium guanylate is a compound with formula Ca(C<sub>10</sub>H<sub>12</sub>O<sub>4</sub>N<sub>5</sub>PO<sub>4</sub>). It is the calcium salt of guanylic acid. It is present in all living cells as part of RNA, and is commercially prepared from yeast extract or fish.
As a food additive, it is used as a flavor enhancer, particularly low-salt products and has the E number E629.