Bioremediation selection, design, and optimization must consider site-specific cost-impacting factors including the depth to the plume, aquifer hydraulic and geochemical properties, contaminant mass and distribution, presence of co-contaminants, required cleanup level, and physical/ logistical constraints of the site.  Many of these factors impact any given in-situ technology, however, impacts on the distribution of microorganisms and/or supporting remedial reagents could raise the cost.  Frequently there is a trade off between capital and operating costs, with the general rule being to minimize the life-cycle costs rather than the initial-capital costs.  Another strategy to significantly reduce remediation costs is to negotiate risk-based remedial objectives as an alternative endpoint to drinking water standards.  This paper will discuss these and other key factors that impact enhanced bioremediation costs and approaches for optimizing the remedial strategy to minimize those impacts.