The P atom in the title mol-ecule, C(12)H(26)N(3)OP, has a distorted tetra-hedral configuration: its bond angles lie in the range 101.1 (2)-119.1 (2)°. The P-N bonds to the two cyclo-pentyl-amido moieties are significantly different [1.619 (4) and 1.643 (4) Å], with the shorter bond related to an anti orientation of the lone electron pair of the corresponding N atom relative to the P=O bond. The O atom of the P=O group acts as a double hydrogen-bond acceptor and is involved in two different inter-molecular N-H⋯O(P) hydrogen bonds, building R(2) (2)(8) rings that are further linked into chains along [001].