We report the first large format (640 x 512) AlInAs-InGaAs quantum-well infrared photodetector (QWIP) focal plane array (FPA), and investigate the characteristics of AlInAs-InGaAs QWIPs both at pixel and FPA level. The measurements on the detectors fabricated with molecular beam epitaxy grown epilayer structure including 30 InGaAs quantum wells (26 A thick, N-D = 2 x 10(18) cm(-3)) yielded very promising characteristics. The detectors with lambda(p) = 4.2 mu m and Delta lambda/lambda(p) = 25% displayed a background-limited performance temperature as high as 105 K with f/2 aperture. The noise equivalent temperature difference of the FPA is as low as 23 mK (f/1.5) at 105-K sensor temperature with 99.6% operability. These results are comparable to the best results reported for AlGaAs-InGaAs midwavelength infrared QWIPs showing the promise of this material system for completely lattice-matched multiband QWIP FPAs.