A portable and collapsible isolator is taught for containing radioactive, chemical or biological agents. The isolator is comprised of a collapsible frame, movable between a collapsed transport position and an open operational position, and a flexible and collapsible envelope in the form of an airtight bag attached to the frame to define a cavity. The envelope remains airtight in both the collapsed and open positions. One or more sealable openings are formed in the envelope for insertion and removal of the radioactive, chemical and biological agents into and out of the cavity. The isolator may optionally include at least one glove extending from one or more of said sealable openings into the cavity, for handling said radioactive, chemical and biological agents inside the cavity.