The epithelial sodium channel (ENaC) mediates the first step in Na⁺ reabsorption in epithelia cells such as kidney, colon, and airways and may consist of four homologous subunits (, , , ). Predominantly, the -subunit is expressed in these epithelia and it usually forms functional channels with the - and -subunits. The -subunit was first found in human brain and kidney but the expression was also detected in human cell lines of lung, pancreatic and colonic origin. When co-expressed with and accessory subunits in heterologous systems the two known isoforms of the -ENaC subunit (1 and 2) can build amiloride-sensitive Na⁺ channels. In the present study we demonstrate the expression and function of the -subunit in human nasal epithelium (HNE). We cloned and sequenced the full-length cDNA of the -ENaC subunit and could show that in nasal tissue at least isoform 1 is expressed. Furthermore, we carried out Western blot analyses and compared the cell surface expression of the -subunit with the classically expressed -subunit by using immunofluorescence experiments. Thereby, we could show that the quantity of both subunits is almost similar. Additionally, we show the functional expression of the -ENaC subunit with measurements in modified Ussing chambers and demonstrate that in HNE a large portion of the Na⁺ transport is mediated by the -ENaC subunit. Therefore, we suppose that the -subunit may possess an important regulatory function and might interact with other ENaC subunits or members of the DEG/ENaC family in the human respiratory epithelium.