Soil fauna have generally remained an 'unseen' resource to Australian cotton growers. No studies have investigated the effects of cotton fanning practices and insecticides on beneficial soil fauna since the 1970's (Bishop and Blood, 1977 & 1980; Room, 1979). This study (Lytton-Hitchins, 1998) was a baseline biodiversity survey of the principal soil faunal groups found in irrigated cotton fields of north western New South Wales. Field work was conducted on commercial cotton farms located in the Macquarie, lower Nanioi, and Gwydir valleys. The various growers and agronomists involved were practitioners of innovative and 'best management' practices. Fields sampled differed in (i) the age of cotton production and (it) the crop protection practices used to control insect pests. Some field experiments were conducted using whole cotton fields that were unreplicated, whilst others used large replicated plots within whole fields on commercial cotton farms. At the Australian Cotton Research institute (ACRl), a small field with replicate plots of Envirofeast cotton and lucerne was also sampled. Standardised experimental designs were devised and sampling equipment constructed. Surface active species were collected using pitfall traps, visual ground searching, and hand collection. Pitfall trapping periods were usually aligned with irrigation cycles. Extensive field observations were included to determine species-specific behavioural patterns, identify key refugia, and collect species that might avoid pitfall traps. Soil cores were used to sample soil fauna in rhizosphere soil to a depth of 150 mm. Springtails, soil-dwelling beetles, ants, and earwigs were considered in detail, and identified to species or morphological-species. Beetles and earwigs were assigned 'reported' feeding habits, and ants and springtails allocated to functional groups.