In the title compound, 4-amino-7-(2-deoxy-beta-D-erythro-pentofuranosyl)-5-fluoro-7H-pyrrolo[2,3-d]pyrimidine, C11H13FN4O3, the conformation of the glycosyl bond lies between anti and high anti [chi = -101.1 (3) degrees ]. The furanose moiety adopts the S-type sugar pucker (2T3), with P = 164.7 (3) degrees and tau = 40.1 (2) degrees . The extended structure is a three-dimensional hydrogen-bond network involving a C-H...F, two N-H...O and two O-H...O hydrogen bonds.