To assess the relationship between early lymphocyte recovery and outcomes after allogeneic hematopoietic stem cell transplantation (SCT) for acute leukemia in remission, 79 adult patients (AML: 48, ALL: 31) who received transplantation between January 2000 and November 2009 were retrospectively analyzed. The median lymphocyte count on day 30 after SCT (LC30) was 465/µl (range, 10∼2640). On comparison of clinical outcomes between patients with low (LC30<400/µl) and high (LC30≥400/µl) counts, the 5-year overall survival (OS) was significantly better in high LC30 group than in low LC30 group (81.6 vs. 52.6%, p=0.014), but the cumulative relapse rate (RR) and non-relapse mortality (NRM) at 5 years did not differ between the two groups. On multivariate analysis, low LC 30 (HR, 2.44; 95% CI, 1.02∼5.88; p=0.046) and grade II∼IV acute graft-versus-host disease (HR, 2.41; 95% CI, 0.99∼5.90, p=0.0053) were significantly associated with worse OS. However, LC30 was not a risk factor for RR or NRM. These findings suggest that LC30 may be one of the outcome predictors for patients receiving SCT.