We observe electron magnetism originating from fractional quantum Hall states in single-layered GaAs heterojunctions. This magnetization is entirely governed by electron-electron interaction effects. The studies were performed at temperatures between 0.3 and 7 K on gated high-mobility two-dimensional electron systems. We observe oscillations in the magnetic moment at various fractional filling factors, both for ν<1 and ν>1, which persist up to 3.8 K. Most prominent features are found at filling factors 1 / 3, 2 / 3, 4 / 5, and 8 / 5. In addition, an intrinsic strongly asymmetric magnetization around ν = 1 is observed.