Ayrampo (Opuntia soehrensii) seed extracts (AE), traditionally used in the Andean region as source of pigments, were investigated for betacyanins (BC), total phenolic compounds (TPC) and antioxidant capacity (AC). BC stability at 80C up to 90 min at pH 3, 4 and 5, during storage at 4 and 25C, and in yogurt (0.1 and 3% fat) was compared with red beet extracts (RBE). BC half-lives (t1/2) were similar between AE and RBE at 80C, but during storage at 4 and 25C, t1/2 of AE were approximately threefold and twofold (272 and 26 days) of the respective RBEt1/2 (95 and 13 days). Color retention of dyed yogurts was not influenced by fat content, but AE showed better color retention (∼95%) at 4 weeks of storage compared with RBE (∼91%). Overall, these results demonstrate that ayrampo seeds contain BC and phenolics that contribute to AC with great potential as a natural colorant for functional foods. Practical Applications: Aqueous extracts from ayrampo seeds constitute a good source of natural betacyanin pigments and antioxidants. In particular, these extracts showed high stability when subjected to heat treatment and storage. In addition, when used in yogurt at two fat levels (0.1 and 3.0 %); their stability was higher than red beet extracts and comparable with FD&C red no. 40 (synthetic colorant). These results strongly suggest the great potential of ayrampo seed extracts as a source of natural colorant and antioxidants for the growing market of functional foods and dairy products.