The pattern of second primary cancer occurrence in 518 Scottish patients with head and neck cancer was determined by a retrospective study. The overall incidence of second cancers was 9% but the true incidence increased steadily in the years following initial diagnosis to reach a maximum of 21% at 11 years. After 4 years of follow-up patients were more likely to die from a second primary cancer than from the effects of the initial tumour. The Scottish cohort differed from previously reported, overseas, study groups in having a high incidence of second primary cancers in sites outside the upper aerodigestive tract. This potential demographic difference suggests a need for local audit prior to design and implementation of screening protocols for second primary cancers.