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Background and aims: The effects of tillage and N fertilization on CO and CH emissions are a cause for concern worldwide. This paper quantifies these effects in a Mediterranean dryland area. Methods: CO and CH fluxes were measured in two field experiments. A long-term experiment compared two types of tillage (NT, no-tillage, and CT, conventional intensive tillage) and three N fertilization rates (0, 60 and 120 kg N ha). A short-term experiment compared NT and CT, three N fertilization doses (0, 75 and 150 kg N ha) and two types of fertilizer (mineral N and organic N with pig slurry). Aboveground and root biomass C inputs, soil organic carbon stocks and grain yield were also quantified. Results: The NT treatment showed a greater mean CO flux than the CT treatment in both experiments. In the long-term experiment CH oxidation was greater under NT, whereas in the short-term experiment it was greater under CT. The fertilization treatments also affected CO emissions in the short-term experiment, with the greatest fluxes when 75 and 150 kg organic N ha was applied. Overall, the amount of CO emitted ranged between 0.47 and 6.0 kg CO−equivalent kg grain. NT lowered yield-scaled emissions in both experiments, but these treatment effects were largely driven by an increase in grain yield. Conclusions: In dryland Mediterranean agroecosystems the combination of NT and medium rates of either mineral or organic N fertilization can be an appropriate strategy for optimizing CO and CH emissions and grain yield. [ABSTRACT FROM AUTHOR]