Two greenhouse experiments were conducted with strawberries (Fragaria ananassa) grown in plastic pots filled with 12 kg of soil, and irrigated by drip to evaluate the effect of 3 N levels and 3 N sources. The N levels were 3.6, 7.2 or 10.8 mmol Nl−1 and the N sources were urea, ammonium nitrate and potassium nitrate for supplying NH4/NO3 in mmol Nl−1 ratios of 7/0, 3.5/3.5 or 0/7, respectively. Both experiments were uniformly supplied with micronutrients and 1.7 and 5.0 mmoll−1 of P and K, respectively. The fertilizers were supplied through the irrigation stream with every irrigation. The highest yield was obtained with the 7.2 mmol Nl−1 due to increase in both weight and number of fruits per plant. With this N concentration soil ECe and NO3-N concentration were kept at low levels. Total N and NO3-N in laminae and petioles increased with increasing N level. With the N sources the highest yield was obtained with urea due to better fruit setting. The N source had no effect on soil salinity and residual soil NO3-N; residual NH4-N in the soils receiving urea and ammonium nitrate were at low levels.