One hundred eighty male managers participated as age-homogeneous 4-person teams in a validated all-day decision-making simulation. Fifteen teams consisted of 28- to 35-year-old participants (young), 15 teams were in the 45-55 age range (middle-aged), and 15 teams consisted of 65- to 75-year-old (older) persons. More than 40 objective performance measures (loading on 12-15 factors) were calculated on the basis of team decision making, planning, and other indicators. Performance by young and middle-aged teams was generally similar. Older teams made fewer decisions and were less strategic and less responsive to incoming information. Their overview of the task was less broad; action diversity and information search was reduced. However, older teams used opportunities and handled a simulated emergency as effectively as their younger and middle-aged counterparts. Alternative explanations for the obtained differences are presented.