This protocol decribes derivation of TS cell lines from 3.5-days post coitum (dpc) mouse blastocysts. The procedure is similar to the derivation of embryonic stem (ES) cell lines. However, the success rate is considerably higher, and less expertise is required to recognize pluripotent TS cell colonies. - [Read Derivation of Trophoblast Stem (TS) Cell Lines from Blastocysts Protocol]