The feasibility of an Er3+-doped chalcogenide microstructured optical fiber amplifier has been demonstrated via accurate simulations performed by employing an appositely refined, home made, computer code. The optical and geometrical parameters measured on the first samples of microstructured optical fibers together with other physical constants taken by literature are considered in the simulation. The calculated optical gain of the amplifier, made of an Er3+-doped chalcogenide microstructured fiber 2.64 m long, is close to 19.70 dB in the small signal operation, by using a pump power of 200 mW