In the mol-ecule of the title compound, C(19)H(22)N(2)O(2), the pyrazolidinone ring has an envelope conformation, with the C atom attached to the 4-methoxy-phenyl ring displaced by 0.354 (3) Å from the plane of the other ring atoms. The 4-iso-propyl-phenyl ring is oriented with respect to the 4-meth-oxy-phenyl ring at a dihedral angle of 88.94 (3)°. Intra-molecular C-H⋯N hydrogen bonds result in the formation of two planar five-membered rings, which are oriented with respect to the adjacent 4-isopropyl-phenyl and 4-meth-oxy-phenyl rings at dihedral angles of 4.05 (3) and 0.50 (3)°, respectively. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers.