The annual incidence in 14 361 campylobacteriosis cases reported in Finland in 2002–2005 varied between 61 and 76/100 000 population. The mean incidence was highest (148/100 000) in the 25–29 years age group and lowest (range 21–24/100 000) in children aged 5–14 years and patients aged ⩾75 years. The number of domestic cases was low in winter and peaked in summer. A total of 622 strains isolated from domestic infections and 785 foreign travel-related strains were serotyped. Serotypes Pen 3 and Pen 37 had the strongest association with travel-related infections (96%, P<0·001), and Pen 6,7, Pen 12 and Pen 27 were significantly associated with domestic infections (>70% domestic within each serotype, P<0·001). Pen 2 and Pen 1,44 were less common in older than in younger patients. Of domestic strains, a higher proportion of Pen 2 strains was isolated in winter (18%) compared to the other serotypes (0–10%).