Microwave radiation copolymerization of maleic anhydride and allylthiourea was studied in solid state. Composition of the monomer feed and the power and time of microwave radiation on conversion and intrinsic viscosity were discussed. Reactivity ratios for maleic anhydride and allylthiourea were also determined. Values of r(1) and r(2) were 0.875 and 0.650 for maleic anhydride and allylthiourea, respectively. The copolymer can be used as soluble macromolecular complexing agents for metal ions.