Integration of a rye/oat cover crop with liquid swine manure application may enhance retention of manure N in corn-soybean cropping systems. The objective of this study was to evaluate changes in soil inorganic N following injection of liquid swine manure to plots seeded with a rye/oat cover crop. Manure was injected in the fall, 6-8 weeks after a 70% rye/30% oat mixture was drop-seeded into soybean. For 2 consecutive years, we measured surface soil (0-20 cm) NO3-N and NH4-N in the manure injection band and in the non-injected rows every week for up to 6 weeks after manure application and in the following spring before and up to 6 weeks after killing the cover crop prior to corn planting. Soil profile (to 120 cm in 20 cm increments) inorganic N was also quantified before manure application and before the cover crop was killed. Temporal patterns of surface soil NO3-N and NH4-N were different in fall 2005 and fall 2006. Surface soil NO3-N was significantly lower in soil under rye/oat cover crop at 21 d (2005) and 42 d (2006) after manure application, although absolute amounts of NO3-N differed 10-fold. Deep core data indicates the rye/oat cover crop reduces deeper soil NO3-N in the manure band to a depth of approximately 100 cm. Results show that integration of rye/oat cover crop with swine manure reduces soil NO3-N after manure injection which can lower the potential for N leaching after liquid swine manure application.