In the title compound, C(15)H(25)ClN(5)O(4)P, the r.m.s. deviation for the purine ring system is 0.0165 Å. The coordination about the P atom is a distorted tetrahedron [O=P-O angles = 116.70 (6) and 109.87 (6)°]. In the crystal, molecules are linked by N-H⋯O hydrogen bonds, generating a three-dimensional network.