This study took an exploratory look at the effectiveness of an intergroup development OD intervention at different stages of an organization's life cycle. Four simulated organizations were used in the study: one with the intervention in the very early life of the organization (the birth phase), one with the intervention in the growth (or midlife) phase, one with the intervention in the mature (or later life) phase, and a comparison organization with no interven tion. Results suggest that intergroup development interventions can be effective at any life stage, but the impact will be felt in different outcome measures and perceptual measures of organizational processes. Further research in this area should lead to a better understanding of the life cycle influence on the effectiveness of intergroup development and other OD interventions.