Sintered polycrystalline aggregates of forsterite have been deformed in compression. The densities of the samples were higher than 93% of the theoretical density. Creep tests have been performed for a range of grain size (60 to 132 &mgr;m) at high temperatures (T?1450 ¿C) and low stresses (3<&sgr;<20 MPa) in a dead weight creep apparatus at room pressure. The creep law determined is: ? = Cte&sgr;2.5¿0.6exp{(-100 kcal/mole)/RT}. It compares very well to other aggregate or single crystal data.