Post-transplant lymphoproliferative disorder (PTLD) complicates 1 to 10% of all transplantations. Previous clinicopathological studies of PTLD have been limited by small numbers, short follow-up times, outdated data, heterogeneity of pooled solid-organ transplant results, and selective inclusion of early-onset disease. We therefore undertake here a retrospective analysis and identify all cases of PTLD that complicated renal transplantation at the Princess Alexandra Hospital between 30 June 1969 and 31 May 2001. Tumour samples were subsequently retrieved for pathological review and for Epstein-Barr virus-encoded RNA in situ hybridisation (EBER-ISH). Of 2,030 renal transplantation patients, 29 (1.4%) developed PTLD after a median period of 0.5 years (range 0.1 to 23.3 years). PTLD patients were more likely to have received cyclosporine (76% versus 62%, P<0.05), tacrolimus (10% versus 2%, P<0.05) and OKT3 (28% versus 10%, P<0.01). As the burden of immunosuppression increased from dual, to triple, to OKT3 therapy, the risks of early onset, extensive-stage, polymorphic, Epstein-Barr virus (EBV)-associated and fatal PTLD progressively increased. The majority of patients presented with an extra-nodal mass (45%), were afebrile (76%), and had stage-IV disease (60%). EBER-ISH was positive in 58%. Actuarial 5-year disease-free survival was 53.7%. The independent predictors of mortality on multivariate Cox regression were polymorphic histology (HR 7.4, 95% CI 1.5-37) and an international prognostic index (IPI) >1 (HR 2.7, 95% CI 1.1-6.8). Compared with other treatments, chemotherapy was associated with higher survival rates (100% versus 18% at 3 years, P=0.0001). In conclusion, PTLD is more likely, occurs earlier, and is more often fatal, in the setting of intensive immunosuppression. Nevertheless, excellent long-term outcomes are achievable with early recognition and institution of appropriate treatment.