In Chile there is no basic information on the relations established between cadaver decomposition and fungal species, and between these and the environment. In order to assess the fungi present in decomposing skin in four forest ecosystems and one antropized prairie all ecosystems characteristic of south-central Chile, six pig carcasses (Sus scrofa L.) were deposited in each site on Autumn. Skin samples were taken and a record made of the decomposition stage and the soil and climatic conditions. The environmental conditions of the sites affected the speed of decomposition and the variety of fungus species isolated, including Mucorales (Initial stage) and yeasts (Initial stage (1 d), Emphysematous stage (12-25 d) and Active Decomposition stage (26-42 d)). The species identified have been described in the literature associated with soils and keratinous substrates in animal and human cadavers. The results suggest that under the ecosystem conditions existing in south-central Chile on Autumn, the decomposition of pigs' skin is developed initially by populations of Mucorales, to which are added yeasts in the Emphysematous and Active Decomposition stages.