The overall goal of this effort is to develop an economical flame resistant nylon fiber that can be utilized as a component in a new flame retardant (FR) fabric that provides similar physical and mechanical properties to the standard US Army Combat Uniform (ACU) with enhanced FR performance. There is currently no commercially available FR nylon 6/6 fiber, as its processing temperature is around 280°C and most flame retardant additives are only stable to approximately 220-240°C. This study explores a new commercial flame retardant polymer, NOFIA HM1100, that is marketed as an additive to polyesters, but can withstand the higher processing temperatures of nylon. Formulations of FR additive and polyester were produced and evaluated for processibility and for FR performance using microscale combustion calorimetry (MCC) and thermogravimetric analysis (TGA). Bi-component FR fibers were then produced utilizing a sheath/core fiber construction consisting of a FR compound sheathing a nylon 6/6 core and evaluated in the same way. In this way, the mechanical properties associated with using nylon 6/6 are combined with the FR performance of the sheath material. FR loading level and sheath/core composition were investigated to optimize strength and FR performance.