The N-oxide O atom of the minoxidil unit in the 1/1 adduct with lead(II) iodide, [PbI₂(C₉H₁₅N₅O)]_n, bridges two Pb^II atoms, as do each of the I atoms. The bridging inter­actions give rise to a linear chain motif that propagates along the a axis of the ortho­rhom­bic unit cell. The coordination sphere around the six-coordinate Pb^II atom is a distorted -monocapped octa­hedron in which the stereochemically active lone pair caps one of the faces defined by the O and I atoms forming the longer Pb-O or Pb-I bonds. The Pb^II atom lies on a mirror plane; the mirror plane is perpendicular to the pyrimidine ring and it bis­ects the piperidine ring. The aromatic ring is disordered about the mirror plane with respect to the 1-nitro­gen and 5-carbon atoms.