A chip-on-flex package which includes at least one moisture barrier layer to prevent metal corrosion and delamination of flex component layers. An exemplary microelectronic package includes a microelectronic die having an active surface and at least one side, wherein the microelectronic die active surface includes at least one contact. A flex component is attached by a first surface to the microelectronic die active surface. At least one conductive trace is disposed on a second surface of the flex component and extends through the flex component to contact at least one of the contacts. An encapsulation material is adjacent the microelectronic die side and a bottom surface of the flex component. A moisture barrier is disposed on the flex component and the conductive trace(s). A second moisture barrier may be disposed on the encapsulation material. A heat dissipation device may also be incorporated into the chip-on-flex package.