Phakomatosis pigmentovascularis (PPV) is a rare congenital naevoid syndrome; most case reports originate in Japan. The major clinical manifestations consist of coexisting extensive naevus flammeus and pigmentary naevus with or without systemic involvement. We report an 8-year-old Taiwanese boy, who was born with extensive naevus flammeus and other anomalies comprising persistent aberrant Mongolian spot-like pigmentary patches, leg-length discrepancy, pelvic obliquity, scoliosis and bilateral melanosis oculi bulbi. Further investigation also revealed agenesis of the right kidney. The cutaneous lesions remained unchanged over a 3-year follow-up period. Within the classification of PPV, this boy's disorder represents an example of PPV IIb. Right kidney agenesis, which has never been observed in PPV, may be an incidental finding.