Carbon dioxide (CO2) is released from the soil into the atmosphere through the processes of soil respiration, and its amount depends on numerous factors such as agroecological conditions and the type of grown culture. By choosing suitable varieties/hybrids, soil respiration can be reduced. Therefore, the aim of this work is to determine the degree of soil respiration and its seasonal variability, as well as microclimate conditions under different maize hybrids during one vegetation season. Research was conducted near Osijek city, by the closed static chambers method. Statistical data analyses determined the seasonal variability of soil respiration and agroecological conditions for all investigated hybrids, as well as the differences in individual months between the investigated maize hybrids. Average monthly soil respiration was highest in June (12.8 kg ha−1 day−1) and lowest in October (7.1 kg ha−1 day−1). The average annual values of soil respiration and agroecological conditions did not differ significantly between the investigated maize hybrids, and a significantly lower degree of soil respiration was recorded on bare soil. Average annual soil respiration was weakly negatively correlated with soil moisture (r = -0.28) and was not correlated with soil temperature (r = 0.09). However, the determination of the total carbon budget within maize agroecosystem is needed, in order to determine the most suitable hybrid in the light of climate change mitigation.