This letter proposes a compact internal antenna of the modified planar inverted F antenna (PIFA) type with a parasitic patch. It also considers the influences of the handset case and battery. A low-profile design is implemented on both the top and bottom sides of the FR-4 substrate. The proposed antenna, with the small size of 27.5 x 12 x 7 mm(3), can be easily placed in the actual handset. The measured bandwidths of the proposed antenna with handset case and battery (VSWR < 2) can cover 140 MHz (1740-1880 MHz) in the Korean personal communication service (KPCS) band and 90 MHz (2400-2490 MHz) in the Bluetooth band. Numerical simulation and experiment results of antenna electrical performance are investigated by considering the antenna, the phone case, and the battery.