In this paper, an ultra-low power (ULP) 16Kb SRAM-based first-in first-out (FIFO) memory is proposed for wireless body area networks (WBANs). The proposed FIFO memory is capable of operating in ultra-low voltage (ULV) regime with high variation immunity. An ULP near-/sub-threshold 10 transistors (10T) SRAM bit-cell is proposed to be the storage element for improving write variation in ULV regime and eliminate the data-dependent bit-line leakage. The proposed SRAM-based FIFO memory also features adaptive power control circuit, counter-based pointers, and a smart replica read/write control unit. The proposed FIFO is implemented to achieve a minimum operating voltage of 400mV in UMC 90nm CMOS technology. The write power is 2.09W at 50kHz and the read power is 2.25W at 625kHz.