The objective of this research was to design and test a novel conductive cooling system for controlling heat stress in lactating dairy cows by circulating chilled water through modified DCC waterbeds (Dual Chamber Cow Waterbeds). The system was tested to determine (1) the heat flux between the cooled waterbeds and the cows; (2) the production benefit to heat-stressed dairy cows; (3) the sensitivity of moisture accumulation and heat flux to type and thickness of bedding; and (4) the potential economic benefit. The calculated heat flux of the system was 439 W/m2 when the temperature of the circulating water in the waterbeds was 4.5ºC and was 382 W/m2 when the circulating water temperature was 10.0ºC. This was for live cows and about 1 cm of sawdust bedding. This amount of heat flux is significant compared to the amount of metabolic heat a lactating cow must lose. Conductively cooling the cows with 4.5°C water decreased core body temperature by 1.0°C (p < 0.001), decreased respiration rate by 18 breaths/min (p < 0.001), increased milk yield by 5% (p = 0.04), and increased dry matter intake (DMI) by 14% (p < 0.001) when compared to the control. Cooled cows also spent an additional 0.8 hours lying down during the daytime (9 am to 5 pm) compared to the control cows. A sensitivity analysis was performed to compare moisture accumulation rate and heat flux for two types of bedding (sand and sawdust) at four thicknesses each (0.5, 2.5, 7.5 and 20 cm). In both bedding types, moisture from condensation accumulated in the bedding at 0.5-cm thickness but was mostly eliminated by 2.5-cm or greater thickness. Heat flux decreased exponentially as bedding thickness increased. However, 2.5-cm thick bedding (sufficient to control condensation) still allowed adequate heat flux. An economic assessment of the conductive cooling system predicted a net positive return on investment in climates with six months per year of heat stress conditions but a net negative return in climates with two months per year of heat stress. Future research will include improvements in the design of conductive cooling systems to be more thermodynamically efficient and more economically favorable.