Biosolids applied to agricultural fields, parks, and other areas represent significant sources of estrogen-like endocrine disrupting compound (EEDC) inputs to soil. It is important to determine the bioavailability of EEDCs in soil to inform risk assessment concerning their environmental presence; Eisenia fetida (earthworms) are typically used in traditional in vivo bioavailability experiments. The development of an in vitro bioavailability method will decrease time, expense, and use of solvents in future analyses. A thin-film solid-phase microextraction (TF-SPME) method for determining the bioavailability of several EEDCs detected in biosolids was developed and optimized. It was found that the TF-SPME method could be used to calculate equilibrium porewater concentrations of diethylhexyl phthalate, bisphenol A, benzophenone, and triclosan at environmentally relevant concentrations in artificial soil within 88 min. The potential and limitations of using TF-SPME-generated porewater concentrations to predict E. fetida tissue concentrations are discussed.