To examine the role of rumination in the aftermath of traumatic/stressful events, posttraumatic growth (PTG) and the four types of rumination (i.e., intrusive rumination soon after the event, intrusive rumination recently, deliberate rumination soon after the event, and deliberate rumination recently) were assessed retrospectively for participants from the USA (N=224) and Japan (N=431). The results from a hierarchical regression analysis revealed that the hypothesized relationships among the four types of rumination and PTG were largely supported. Intrusive rumination soon after the event was positively related to PTG but recent deliberate rumination most strongly predicted the current levels of PTG for both samples. Some evidence for cultural differences in the role of rumination in PTG was also observed. In the US sample, deliberate rumination recently was more important than the deliberate rumination in the immediate aftermath of the traumatic/stressful event, whereas in the Japanese sample, deliberate rumination both soon after and recently were positively related to PTG. The results illustrate the importance of considering rumination as multidimensional and as varying across time in its impact on PTG. Future directions and clinical implications were discussed.