In a prevalence study of oral mucosal lesions carried out 1973-1974, 20,333 individuals, aged 15 years or above were examined. Chronic lip fissures were found in 110 people, corresponding to a prevalence rate of 0.57%. The fissures were more prevalent among males (0.92%) than females (0.20%) and more prevalent in the age groups below 45 years than in those above. In 1976-1978, 7 patients with annoying, chronic lip fissures were treated by excision. The mean observation time was 26 months (range 17-33 months). No recurrences of the fissures were observed. Histologic examination revealed a chronic inflammatory non-specific infiltrate and no dysplasia or cellular atypia was seen.