Allogeneic transplantation for renal cell carcinoma has shown encouraging preliminary results. We reviewed the published literature to evaluate the impact of patient selection. Most studies did not include information on prognostic factors. We used patient entry rank within individual studies as a novel surrogate for patient selection, motivated by our own experience of an apparent impact of entry rank. One hundred patients were identified from nine studies. Twenty-six per cent of patients demonstrated either a partial or complete response. Median overall survival was 12.3 months. Grade 2-4 acute graft-versus-host disease correlated with an increased likelihood of response (odds ratio: 5.4, 95% confidence interval: 1.6-18.1, P = 0.006) but not survival. Earlier patient entry rank on each trial was associated with a higher probability of response (P = 0.004) and superior survival (P = 0.004). Patient entry rank served as a powerful prognostic factor, suggesting bias in patient selection that evolved over the course of the study. Further studies are warranted to determine the influence of order of patient entry in other early clinical trial settings.