We study the well-posedness of the fractional degenerate integro-differential equations () ∶ ()() = () + ∫ −∞ (−) () + ∫ −∞ (−) () + (), (∈ ∶= [0, 2 ]), in Lebesgue-Bochner spaces (;) and Besov spaces , (;), where , and are closed linear operators on a Banach space satisfying () ∩ () ⊂ (), () ∩ () ≠ {0}, > 0 and , ∈ 1 (ℝ +). We completely characterize the well-posedness of () in the above vector-valued function spaces on by using operator-valued Fourier multiplier. We also give an example that our abstract results may be applied.