A study was conducted at the Institute of Agricultural Technology and Biosystem Engineering, vTI, Germany during the year 2008 to focus on the determination of equilibrium moisture content (EMC) of some bioplastic materials that could be used for agricultural foil mulch. EMC is very important to determine the desirable conditions of microorganism’s growth, which causes material deterioration and degradation. Five commercial bioplastic mulches such as Bioflex, Ecoflex, Chitosan, Mater-bi and Bi-OPL were tested at varying temperature (10-50°C) and relative humidity (43-95%). EMC of all materials increased with the increase in relative humidity and decreased with increase in temperature. However, the relative humidity had a greater effect on the change of moisture content than the temperature. The data revealed that Mater-Bi and Chitosan increased EMC by 9.87 and 12.22 percent, respectively by changing the relative humidity from 43 to 95 percent. These changes of relative humidity increased EMC by 1.41, 2.4 and 0.5 percent for Ecoflex, Bioflex and Bi-OPL, respectively.