An acute leukemia diagnosis can be an extremely stressful experience for most patients. Posttraumatic growth (PTG) is positive psychological change experienced following a struggle with highly challenging life circumstances. The current study is the first longitudinal investigation of predictors of PTG and distress in adult acute leukemia patients undergoing induction chemotherapy. Findings suggest that these patients report PTG, and levels of PTG appear to increase over the weeks following leukemia diagnosis and induction chemotherapy. Variables associated with higher total PTG scores over time included greater number of days from baseline, younger age, and greater challenge to core beliefs. Variables associated with higher distress included greater number of days from baseline, greater perceived cancer threat, higher symptom severity, and lower spiritual well-being. Results underscore the critical role that examination of one's core beliefs may play in the development of PTG over time.