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The purpose of this study was to evaluate, during the phenological stages of inoculated soybean crop [Glycine max (L.) Merrill], the effect of different N fertilization levels and inoculation with Bradyrhizobium japonicum on N 2 O emissions from the soil. Gas emissions were evaluated at field conditions by the static-chamber method. Nitrogen fertilization increased N 2 O emissions significantly (P< 0.05). The variable that best explained cumulative N 2 O emissions during the whole soybean growing season was the soil nitrate level (r 2 =0.1899; P=0.0231). Soil moisture presented a greater control on N 2 O emissions between the grain-filling period and the crop commercial maturity (r 2 = 0.5361; P < 0.0001), which coincided with a positive balance of the available soil N, as a consequence of the decrease in crop requirements and root and nodular decomposition. Only soil soluble carbon (r 2 =0.29; P= 0.019) and moisture (r 2 =0.24; P=0.039) were correlated with N 2 O emissions during the residue decomposition period. The relationship between soil variables and N 2 O emissions depended on crop phenological or stubbles decomposition stages.