Compressional behavior of fabrics is important in most enduses. The traditional compression teaster such as KESF (Kawabata Evaluation System for Fabrics) and FAST (Fabric Assurance by Simple Testing) systems are used to perform off-line static measurements. The principle of online measurement of compressional behavior being developed is based on the analysis of fabric deformation while the fabric moves through a nip formed by a pair of rollers, one of which is controlled by a motor and is attached to a load cell. The specimen being tested is moved continuously through the measurement system, while it is deformed in compression at a constant rate in the nip area. The load displacement relation of the fabric is then obtained as a functional of time. Assuming a stepwise anisotropic behavior in the thickness direction, the fabric stress-strain relation in compression is obtained.