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In the Lorraine region, major soils used for winter oilseed rape are calcareous. Across two pot and two field experiments, we studied the influence of sulfur applied at different levels on apparent N-use efficiency (ANU), yield, glucosinolate (GLS) and oil content of seeds. The soil received a constant dose of 200kg Nha⁻¹ as ammonium nitrate, urea or cow slurry and three levels of S: 0, 30 and 75kgha⁻¹ as ammonium thiosulfate (ATS), MgSO₄ or ATS plus MgSO₄. Apparently, oilseed rape is a N-inefficient crop as revealed by low ANU values which varied within 36 and 53% from field experiment versus 25 and 61% under controlled conditions. In both cases, S additions improved N-use efficiency only at the highest dose of 75kg Sha⁻¹, which is not attained by ATS with 35kg Sha⁻¹ (10% v/v). S fertilization increased the GLS contents that were found to be negatively correlated with plant N/S uptake ratios observed at …