Electrospinning and its application in filtration area are worthwhile to look into as the large surface-to-volume ratio of nanoweb may affect the filtration efficiency by possibly giving more particle-capture sites. In this study, Nylon 6 is electrospun to produce ultra-fine nonwovens, and its characteristics as filter media are investigated. Electrospinning parameters including solution concentration, tip-to-collector distance, and the feed rate are changed in producing nonwovens in different fibre size distribution ranging from 50 to 150 nm in diameters. The solution concentration of 10 and 12 wt% produced the fibres with the average diameter of around 85 nm, where 15 wt% solution produced larger fibres with the average diameter of 121 nm. Finer fibres were able to process at longer tip-to-collector distance and at slower feed rate. The electrospun media that are processed at different spinning conditions are evaluated for its filtration efficiency and pressure drop. The electrospun nanofibre media shows the potential in application as HEPA and ULPA grade filter media, by comparing the filtering performance of nanoweb with the conventional melt-blown nonwoven media. (C) 2009 Elsevier Ltd. All rights reserved.