Nitrogen balances from 283 conventional dairy farms situated in southern Sweden were investigated using the farm gate method. Nitrogen balances were determined for 1997 and 1998. Three N balances were calculated; for the whole farm, for crop production and for milk production. The aims of the investigation were to study if factors such as manure handling system, the amount of N obtained from mineral fertilizer per hectare and the proportion of sugar beet have an influence on the N balance. There was no significant effect of manure handling system on the N surplus per hectare or on N efficiency. The results showed that N efficiency was significantly improved by including sugar beet in the crop rotation and was negatively correlated with milk yield per hectare and fertilizer N per hectare. The N surplus per hectare was positively correlated with milk yield per hectare and fertilizer N per hectare. The comparison did not find a strong relationship between the amounts of N obtained from mineral fertilizer per hectare and supplied as manure. The latter was calculated theoretically. There was a weak, but significant, negative correlation between N from manure in 1997 and N from mineral fertilizer in 1998.