Stocking hatchery-reared muskellunge Esox masquinongy is important to Wisconsin’s muskellunge management program. Typically, large (8–12-in) fingerlings are stocked in fall; however, these fish have poor short-term (30–60-d) survival. To assess survival and cost-effectiveness (maximizing return per dollar invested), both over winter and to age 18 months, I compared success of fish stocked as fall fingerlings (FF) and spring yearlings (SY). Overwinter survival of FF averaged 19% (N = 14; range, 2.7–43.3%). Mortality was highest from stocking through late fall, then declined over winter. In three lakes stocked with both FF and SY, SY survived better (19%) than FF (4%) to age 18 months. Cost analysis based on survival over winter revealed no consistent economic advantage in stocking larger, more expensive fingerlings within the 8–12-in range unless precise information is known about potential predators. Cost comparisons indicated SY were one to four times more cost-effective than FF to age 18 months. Stocking SY should provide a better return to the fishery per hatchery dollar than stocking FF.