The density‐area relationship has received considerable attention recently. A limitation of empirical examinations of the density‐area relationship is that they have been conducted over short time spans, focusing on within-generation mechanisms such as dispersal and ignoring potential between-generation effects. I used simulation modeling to investigate the effects of both within- and between-generation factors that vary with patch size on the density‐area relationship. In general, between-generation factors had a greater effect on long-term density‐area patterns than within-generation processes, but within-generation processes are important under certain conditions. Interactions between within- and between-generation processes produced several non-intuitive results. The results of this study demonstrate that to fully understand density‐area patterns both within- and between-generation patterns must be investigated. © 1999 Elsevier Science B.V. All rights reserved.