We studied GVHD after donor lymphocyte infusion (DLI) in 328 patients with relapsed CML between 1991 and 2004 . A total of 122 patients (38%) developed some form of GVHD. We analyzed GVHD by clinical presentation (acute or chronic GVHD) and onset time after the first DLI (early ( ≤ 45 days) or late (>45 days)). There was a significant overlap between onset time and clinical presentation. Some form of GVHD occurred at a median of 104 days, acute GVHD at 45 days and chronic GVHD at 181 days after DLI. The clinical presentation was acute GVHD in 71 patients, of whom 31 subsequently developed chronic GVHD subsequently. De novo chronic GVHD was seen in 51 patients. OS for all patients was 69% (95% confidence interval (CI) 63-75) at 5 years, DLI-related mortality was 11% (95% CI 8-15) and disease-related mortality was 20% (95% CI 16-25). Risk factors for developing GVHD after DLI were T-cell dose at first DLI, the time interval from transplant to DLI and donor type. In time-dependent multivariate analysis, GVHD after DLI was associated with a risk of death of 2.3-fold compared with patients without GVHD. Clinical presentation as acute GVHD and early onset GVHD were associated with increased mortality.