In this paper, we consider a Riesz–Feller space‐fractional backward diffusion problem with a time‐dependent coefficient
ut(x,t)=ℓ(t)xDθγu(x,t)+f(x,t),(x,t)∈R×(0,T).
We show that this problem is ill‐posed; therefore, we propose a convolution regularization method to solve it. New error estimates for the regularized solution are given under a priori and a posteriori parameter choice rules, respectively. Copyright © 2016 John Wiley & Sons, Ltd.