context: studies in the area of health economics are still poorly explored and it is known that the cost savings in this area is becoming more necessary, provided that strict criteria. objective: to perform a cost-effectiveness analysis of spinal anesthesia versus local anesthesia plus sedation for loop colostomy closure. methods: this was a randomized clinical trial with 50 patients undergoing loop colostomy closure either under spinal anesthesia (n = 25) or under local anesthesia plus sedation (n = 25). the duration of the operation, time spent in the post-anesthesia recovery room, pain, postoperative complications, length of hospital stay, laboratory and imaging examinations and need for rehospitalization and reoperation were analyzed. the direct medical costs were analyzed. a decision tree model was constructed. the outcome measures were mean cost and cost per local and systemic postoperative complications avoided. incremental cost-effectiveness ratios were presented. results: duration of operation: 146 ± 111.5 min. vs 105 ± 23.6 min. (p = 0.012); mean time spent in post-anesthesia recovery room: 145 ± 110.8 min. vs 36.8 ± 34.6 min. (p<0.001). immediate postoperative pain was lower with local anesthesia plus sedation (p<0.05). local and systemic complications were fewer with local anesthesia plus sedation (p = 0.209). hospitalization + rehospitalization: 4.5 ± 4.1 days vs 2.9 ± 2.2 days (p<0.0001); mean spending per patient: r$ 5,038.05 vs 2,665.57 (p<0.001). incremental cost-effectiveness ratio: r$ -474.78, indicating that the strategy with local anesthesia plus sedation is cost saving. conclusion: in the present investigation, loop colostomy closure under local anesthesia plus sedation was effective and appeared to be a dominant strategy, compared with the same surgical procedure under spinal anesthesia.