A retrospective study was undertaken to assess causes of maxillofacial fractures in Helsinki in 1981 and 1997. Hospital records of 725 patients were analyzed according to several factors including age, sex, cause of fracture and time of the injury. The time intervals between the accident and hospital examination were also evaluated. Number of maxillofacial fractures was 318 in 1981 and 407 in 1997 (27.9% increase) and most patients were men. The male to female ratio was 2.8:1 in 1981, 3:1 in 1997. In 1981, most affected patients were in the age group of 31-40 years (33.2% of men, 28.9% of women). Sixteen years later the most affected age group was 41-50 years (23.3% of men, 30.4% of women). Assault was the cause of the injury in 42% of patients followed by traffic accidents (26%) and fall (17%). During the study period violence had become more severe in nature. Kicking as the cause of maxillofacial fracture increased by 7.3% and use of a weapon by 5.7% between the years studied. Bicycle accidents increased by 19.3% but motor vehicle accidents decreased by 31.6% between the years. Falls, and bicycle and pedestrian accidents were the causes that accounted for most of the increase in maxillofacial fracture. In 1997, maxillofacial fractures were slightly more common from June to August and from Friday to Sunday than at other times (45.2 and 50%, respectively).