A few studies have shown that amine compounds (e.g., hydroxylamine) can be co‐metabolically introduced into the reaction pathway of denitrification. During this microbial process, the N atom of the amine species is bound to a N atom of nitrite. In case of hydroxylamine, this concomitant reaction ultimately results in the formation of hybrid N2O. Due to its co‐metabolic character the process has been termed co‐denitrification. Hybrid N2O production during co‐denitrification has been proven to occur in prokaryotic (e.g., Pseudomonas sp.) as well as eukaryotic (e.g., Fusarium sp.) species. Many of them are already well‐known as common denitrifiers. However, until now no clear evidence has been provided to show that N2O production by co‐denitrification really takes place in a soil. In the present study, a formation of hybrid N2O was revealed by an adapted 15N‐tracer model, when both hydroxylamine and 15N‐nitrate were applied (mol ratio 10:1) to an anaerobically incubated soil suspension from a Haplic Chernozem. The presence of hybrid N2O was also indicated by a novel characteristic factor (Rbinom) developed for a hybrid‐N‐N‐gas detection. By contrast, no hybrid N2O was found when either an autoclaved soil suspension, only nitrate or only hydroxylamine was used. Thus, it appears that hybrid‐N2O formation occurred due to co‐denitrification of hydroxylamine. Hence, this is the first study which demonstrates hybrid‐N2O production by co‐denitrification beyond a microbial species level. The 15N‐tracer model revealed that under the given experimental conditions N2O production by co‐denitrification prevailed against N2O from denitrification and abiotic hydroxylamine decomposition. In addition, a formation of hybrid N2 was also calculated by the model. However, the experimental results lead to the conclusion that it was most likely caused by a reduction of hybrid N2O due to conventional denitrification.