A Hawaiian theme restaurant in the country of Wales was the source of an outbreak of Campylobacter jejuni serotype HS50, phage type 49. The restaurant specialized in stir-fried dishes. Illness was associated with eating stir-fried chicken pieces. A dose-response relationship between risk of illness and the amount of chicken consumed was observed. The chicken pieces were large and probably contributed to undercooking of the chicken. No food samples were available for laboratory testing.