Blends of the alternating ethylene-tetrafluoroethylene copolymer (ETFE) with poly(vinylidene fluoride) (PVF2) were prepared by melt-mixing. Compatibility, morphology, thermal behavior, and mechanical properties of the ETFE/PVF2 blends with various compositions were studied by using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), tensile tests, and scanning electron microscopy (SEM). DMA studies showed that the blends have separate glass transition temperatures (T-g) close to those of the pure polymers. ETFE and PVF2 are incompatible. Marked negative deviations from simple additivity were observed for both the ultimate strength and the elongation at break over the entire composition range. The interfaces between ETFE and PVF2 are weakly bonded with rather poor interaction. SEM observations revealed that the blends have a two-phase structure and the adhesion between the phases is poor.