Nitrate nitrogen losses with subsurface drainage water from drained Stagnosols were studied in field experiment with different mineral nitrogen rates in the period from 1997 to 2004. Trial treatments were: 1.Check–unfertilized, 2. N0 PK, 3. N100 PK, 4. N150 PK, 5. N200 PK, N250 PK, N250 PK + Phosphogypsum, N250 PK + Zeolite tuff + CaCO3, 9. N300 PK and 10. Black fallow. The experimental station soil type is defined as Stagnosols, with Ach+Ecg – Ecg – Btg sequence of soil horizons. Due to its physical (high content of fine sand, silt and clay) and chemical properties (calcium deficiency, low content of organic matter), this soil type has limited fertility. Intensive mineral fertilization is very important for arable farming at given conditions. Because of water stagnation in soil profile drainpipes were installed at the average distance of 20 m. Area of each fertilizing treatment embedded two drainpipes in their full length. In the treatment involving black fallow, all tillage practices were the same as in other trial treatments, including also supplementary tillage practices. On experimental plots, crops were grown in the following crop sequence: 1998/99 and 2003/04 - maize (Zea mays), 1996/97, 1999/2000 and 2002/03 - winter wheat (Triticum aestivum), 1997/98 and 2000/01 oilseed rape (Brassica napus var. oleifera), 2001/02 soybean (Glycine hispida max.). The trial plot size was 30x130 m (3900 m2) for each treatment, as conditioned by the drainpipe spacing and their length (130 m). Water samples were taken on a daily basis, and average sample was prepared every 5-7 days to be used for chemical analysis of water. NO3- N concentration in drainage water varied in dependence on the quantity of mineral nitrogen applied, on the quantity and intensity of precipitation, and on the drainage volume. In treatments without mineral nitrogen application, viz. in the check treatment and in the treatment fertilized with phosphorus and potassium, the average NO3- N concentration was relatively low. Increased rates of applied mineral nitrogen led to higher average values of NO3- N concentration in drainage water. At the treatments with 100 and 150 kg ha-1 N, average nitrate nitrogen concentration was lower than 10 mgL-1 for all years. At the treatments with higher doses of nitrogen concentration of NO3- N in drainage water were also higher, and they were in relation with quantities of applied nitrogen. Maximum average concentrations went up to 30 mgL-1 NO3- N at treatment with 300 kg ha-1 N. Average nitrate nitrogen leaching in drainpipe water from treatments 1 and 2 where crops were grown without mineral nitrogen fertilization varied from 7.0 to 7.9 kg per hectare. Compared to that, average nitrate nitrogen leaching at black fallow treatment was higher – 10.7 kgha-1. Nitrate nitrogen leaching in drainpipe water from treatments with mineral nitrogen fertilization varied from 8.4 kgha-1 at the treatment with 100 kgha-1 N up to the 30.1 kgha-1 at the treatment with 300 kgha-1 N. NH3 nitrogen losses were lower that 1 kgha-1 N and they were not influenced by the quantities of applied nitrogen. Compared to the average quantity of nitrogen applied, average quantity of nitrogen leached in drainpipe water from different trial treatments varied from 8 to 12% of applied mineral nitrogen. Results substantiate the importance of investigating the influence of different mineral nitrogen rates upon its leaching from Stagnosols in the agroecological conditions of Croatia, notably in regions where intensive agricultural production is practiced. Key words: Stagnosols, Subsurface drainage, Nitrogen, Leaching.