MammalTIS is a dedicated database for mammalian translation initiation sites, providing candidate TIS annotations across human and mouse transcriptomes. All candidate TISs and associated annotations were obtained through standardized processing and integrative analysis of public translation initiation profiling datasets. MammalTIS provides a searchable resource to support studies of mammalian translational regulation. The current version of MammalTIS was released on 2026-08-27.