The purpose of this analysis of health economic studies in the field of oncology was to investigate among sponsored studies whether any relationship could be established between the type of sponsorship and (1) type of economic analysis, (2) health technology assessed, (3) sensitivity analysis performed, (4) publication status, and (5) qualitative conclusions about costs. The Health Economic Evaluations Database (HEED, version 1995-2000) was searched on the basis of oncological ICD-9 codes, sponsorship, and comparative studies. This search yielded a total of 150 eligible articles. Their evaluations were prepared independently by two investigators, on the basis of specific criteria. When evaluators disagreed, a third investigator provided a deciding evaluation. There was no statistically significant relationship between the type of sponsorship and sensitivity analysis performed (P=0.29) or publication status (P=0.08). However, we found a significant relationship between the types of sponsorship and of economic analysis (P=0.004), the health technology assessed (P<0.0001), and qualitative cost assessment (P=0.002). Studies with industrial sponsorship were 2.56 (99% lower confidence interval (CI)=1.28) times more likely to involve cost-minimisation analyses, were 0.04 (99% higher CI=0.39) times less likely to investigate diagnostic screening methods, and were 1.86 (99% lower CI=1.21) times more likely to reach positive qualitative conclusions about costs than studies supported by nonprofit organisations. In conclusion, our results suggest that there is a greater probability that industry-sponsored economic studies in the field of oncology tend to be cost-minimisation analyses, to investigate less likely diagnostic screening methods, and to draw positive qualitative conclusions about costs, as compared to studies supported by nonprofit organisations.