We retrospectively compared the costs and benefits of brain tumor resection in the conventional operating room (cOR) with the interventional magnetic resonance (iMR) suite from 1993-1998. Comparisons were made for adults (diagnosis-related group (DRG) 001) and children (DRG 003) for length of stay (LOS), hospital charges and payments, hospital total direct and indirect costs, readmission rates, repeat resection (RR) interval, and net health outcome. Statistical analysis was with ANOVA, Dunnett's, and Bonferroni tests. For DRG 001, iMR LOS (3.7 days (d)) was 54.9% shorter than for cOR (8.2 d) for first resections (FR) (P < 0.001) and RR (6.0 vs. 8.7 d (31.0%), P < 0.05). IMR hospital charges were 12.2% lower ($4063) for FR and 4.1% lower ($922) for RR than for cOR. Total iMR hospital costs were 14.4% lower ($3415) than for cOR for FR and 3.3% lower ($723) than costs for RR. Cost-to-charge ratio (c/c) for FR was 69.6% (iMR) and 71.4% (cOR) and for RR 70.9% (iMR) and 71.1% (cOR). For DRG 003, iMR LOS (4.5 d) was shorter than for cOR (14.1 d, P < 0.001) for FR and for RR (8.0 vs. 13.3 d). IMR hospital charges were 43.8% lower than for cOR for FR (P < 0.05) and RR. The iMR costs were lower for FR (46.4%, P < 0.01) and RR (44.7%) than cOR. IMR c/c was 71.4% and 74.8% for cOR. For RR, the iMR c/c was 72.8% and 73.9% for cOR. No RR have followed iMR surgery. COR RR rate was 20% in adults and 30% in children. The mean time from iMR surgery was 11.3 months in adults and 18.0 in children. For the cOR, the mean time to RR was 9.3 months in adults and 13.3 in children. This data suggests that iMR surgery improves net health outcomes by reduced LOS, reduced RR, and reduced hospital charges and costs.