Bioavailability may be measured through direct bioassays, or use of biomimetic methods. Bioassays measuring toxicity, bioaccumulation, and biodegradation endpoints are expensive, laborious, and often specific to the test organisms or conditions. Chemically based methods, on the other hand, have long been sought as alternatives to bioassays for predicting contaminant bioavailability due to their simplicity, speed, reproducibility and low cost. Recent developments have demonstrated that these techniques validated with bioassays may provide a uniform and standard surrogate for measuring bioavailability of organic contaminants in environmental matrices. The chemical techniques adopted so far roughly fall into two groups – partial extraction methods to quantify bioaccessibility, and various equilibrium methods to measure the freely dissolved concentration. Examples of the various methods used to estimate bioavailability, along with their working principles and basic operational procedures, will be reviewed in this presentation. Information gaps meriting further research will be discussed.