Acid Sensing Ion Channels (ASICs) are proton sensitive ion channels expressed in the central and peripheral nervous system of mammals, where they are involved in perception of pain, learning, modulation of synaptic transduction and other processes. ASIC subunits are predicted to have two transmembrane domains connected by an extracellular loop. ASIC1a and ASIC1b are two splice variants of the same gene, which differ in their N-terminus and the proximal part of the extracellular loop. Both subunits share two putative N-glycosylation sites, located in the common part of the extracellular loop. ASIC1b has two additional sites found in the differential part of the loop. We have mutated all the sites in ASIC1a and ASIC1b and combined SDS-PAGE with voltage clamp measurements and cell surface expression experiments to analyse the mutants. There was a large decrease of the amount of functional channels on the cell surface upon disruption of the glycosylation sites. The strongest effect was observed for the sites which are not conserved between the two subunits. Moreover, removing of the common sites had differential functional consequences for ASIC1a and ASIC1b. These results suggest that the N-linked glycans have different implications in ass>sting the folding of the functional subunits.