Objective: We examined the cost-effectiveness of conservative management (CM) compared to planned cesarean hysterectomy (CH) for placenta accreta spectrum (PAS). Design: A cost-effectiveness analysis in a theoretical cohort of patients. Setting : A decision analytic model. Population : A theoretical cohort of 1000 pregnant patients with PAS greater than 20 weeks gestation. Methods : In base case analysis, we assumed that between 20-40% of individuals would be eligible for CM. Model inputs were derived from the literature. Analysis was conducted from a healthcare system perspective with a one year analytic horizon. Outcomes included hysterectomy, surgical site infection (SSI), length of hospitalization, intensive care unit (ICU) admission, and death. An incremental cost-effectiveness ratio (ICER) of $50,000 per quality-adjusted life year (QALY) defined cost-effectiveness. Sensitivity analyses were performed. Main outcome measures: The cost gained per life year and per QALY. Results: For base-case estimates, CM was the cost-saving strategy with an ICER of $9330.51 USD. Compared to CH, CM resulted in 905 fewer hysterectomies, 80 fewer instances of SSI, and 5 fewer deaths. CM resulted in 149 more admissions with length of stay >5 days and 25 more ICU admissions . In probabilistic sensitivity analysis, CM was the cost-effective strategy in 71% of runs and the dominant strategy in 42% of runs. Conclusion: CM was the cost-effective strategy for management of PAS in greater than 70% of iterations of our model. Modeling demonstrated significant uncertainty in the comparative effectiveness of the two strategies, highlighting the need for prospective research evaluating the effectiveness of CM.