Abstract: The objective of this study was to determine whether there was an increase in nitrate concentrations in soil water samples as a result of fertilizer nitrogen (N), in the form of cattle slurry, being applied at various rates to an establishing crop of Miscanthus; this trial was conducted during 2008/09. The crop received either no fertilizer (0-unfertilized control) or an annual application of 60, 120 or 180 kg N ha-1. Soil water solution samples were collected fortnightly from porous ceramic cup samplers. Nitrate (NO3¯) levels in these soil water samples were determined and monitored. In 2008, the soil water nitrate concentrations were high on all treatments, 14, 16 and 20 mg l-1, respectively for 0, 60 and 120 kg N ha-1. However, there was no significant difference between treatments. Soil water nitrate concentrations were again high (12-21 mg l-1) in 2009, particularly at the 180 kg N ha-1 levels which showed significantly higher levels of nitrate leaching when compared to all other treatments. A high level of nitrate is seen as a threat to both public health and natural waters. Of these threats the latter is the more immediate, but the health issue has attracted more public concern, as the presence of nitrate in drinking water has been linked to a number of medical conditions such as blue baby syndrome (methaemoglobinaemia) in infants. The results indicate that leaching losses were closer to those recorded under arable land than extensively managed grassland; slurry application on an establishing Miscanthus crop does not appear to contribute adversely to levels of nitrate in groundwater when compared to other more extensive cropping systems.