Micro- and mini-chemical and thermal reactors are devices that possess small internal features (<500μm high), which allow for increased heat and mass transfer rates between fluids. One method for manufacturing these devices is through Foil Lamination, which is the diffusion bonding of metallic sheets that have been precision machined to produce the internal architecture. This study investigated the influence of diffusion bonding temperature, pressure, and time on the bond strength between metallic sheets and the integrity of the embedded feature. Tensile strength, pressure drop and metallgraphic measurements were made as a function of diffusion bonding condition on test coupons which contained a double lap joint tensile bar and an embedded channel. The results revealed that those conditions that produced good metallurgical joints between the sheets resulted in high back pressures of fluid flowing through the channel. Conversely, those conditions that resulted in poor metallurgical joints resulted in low back pressures. These results were used to select a combination of diffusion bonding conditions for producing devices with optimal performance characteristics.