The present invention provides a process for producing a water-absorbent resin, characterized in that a reverse-phase suspension polymerization of a water-soluble ethylenically unsaturated monomer is carried out in a hydrocarbon dispersion medium comprising a dispersion stabilizer while an azo-based compound and a peroxide are combined in the presence of an internal-crosslinking agent, in that the following formulae are satisfied, 0.10≤B/(A+B)  (1), and 0.055≤B+9×C≤0.120  (2), wherein A mol, B mol and C mol represent used amounts of the azo-based compound, the peroxide and the internal-crosslinking agent, respectively, relative to 100 mol of the water-soluble ethylenically unsaturated monomer used in the polymerization, and in that a post-crosslinking reaction is carried out by adding a post-crosslinking agent after the polymerization. The present invention also relates to a water-absorbent resin having specific performance and produced by the process.