In vitro binding studies with different mycotoxins are often made to test various adsorbents for their ability to detoxify these toxins in animal feed. In this study different clays were investigated for their ability to bind aflatoxin B1, zearalenone, ochratoxin A and deoxynivalenol in two different buffer systems (pH 3 and pH 6.5). In addition chemical/physical properties like cation exchange capacity and the concentration of exchangeable Ca(2+), Na(+), Mg(2+) and K(+) ions in the adsorbents were determined to establish if there is a connection between these parameters and the capacity to bind mycotoxins. Most of the tested clays showed high adsorption rates for aflatoxin B1 in both buffer systems. Adsorption rates for ochratoxin A and zearalenone of the tested clays were in the range of 0-100%. None of the tested adsorbents had the ability to bind deoxynivalenol. In this study no correlation between the cation exchange capacity of the clays or the concentration of exchangeable Ca(2+), Na(+), Mg(2+) and K(+) ions and the ability to adsorb mycotoxins could be investigated.