Acute diverticulitis in the young is increasingly common and is not confined to a particular ethnic or socioeconomic group. The majority of cases are in men and occur in the fourth decade of life. Obesity is the major comorbid condition. The disease appears to be an early manifestation of that seen in the elderly based on identical anatomy and histology. The high incidence of surgical intervention and the high incidence of emergent or urgent intervention, particularly following the initial attack, suggests that this manifestation is a more virulent form of the disease. Because of this, any patient under age 40 should undergo resection following the first documented attack of acute diverticulitis.