Brassicaceous cover crops contain compounds reputed to suppress plant-parasitic nematodes when incorporated; however, little is known about their impact in no-till systems or on free-living nematodes.  Effects of winter-killed oilseed radish (Raphanus sativus) ‘Adagio' were compared to a weedy control in a field experiment from 2003-2005.  Summer crops, soybean (Glycine max) ‘Northrup King S39Q4' in 2004 and corn (Zea mays) ‘Pioneer 34B62' in 2005, were planted no-till or after disking.  No differences among treatments were found for plant-parasitic nematodes. Rhabditidae dauer larvae populations were higher across dates in oilseed radish (2,376 nematodes kg^-1 dry soil) compared to the weedy control (259 nematodes kg^-1 dry soil).  The Enrichment Index was lower in no-till compared to disked plots in summer 2005, indicating fewer available resources for opportunistic nematodes.  A second experiment (no-till) was established in fall 2004 with cover crop treatments of rapeseed (Brassica napus) ‘Dwarf Essex', forage radish (R. sativus) ‘Dikon', rye (Secale cereale) ‘Wheeler', oilseed radish and a weedy control.   Plant-parasitic nematode populations did not differ among treatments; however, populations of Coslenchus sp. (suspected to feed on root-hairs and fungi) were higher in rye and rapeseed (2,026 and 2,500 kg^-1 dry soil) compared to the control and radishes (374 and 81 kg^-1 dry soil) in summer 2005.  Bacterial-feeding nematodes increased from 1,814 kg^-1 dry soil in the control to 6,259 and 3,759 kg^-1 dry soil in forage and oilseed radish, respectively.  Rhabditidae dauer larvae were more abundant in forage radish than the control and rapeseed.  Brassica cover crops may have limited potential for plant-parasitic nematode suppression in no-till systems.  Results demonstrate that cover crops have unique impacts on nematode communities; however, the implications of these effects are not yet understood.  The ecological roles of Rhabditidae dauer larvae and Tylenchidae nematodes should be investigated further.