Soil aggregates can provide effective protection of organic carbon (OC) from microbial decomposition. There is no systematic method for estimating the amount of protected carbon within aggregates. However, difference between CO2 emissions from incubation of intact versus crushed aggregates have been widely used as a proxy for OC physical protection within aggregates. There is no global analysis on this type of experiment nor on the drivers of the amount of OC physically protected in soils yet. Using a meta-analysis including 165 pairs of observations from 22 studies encompassing a variety of agro-ecosystems, climate and soil types, we investigated the crushing effects on cumulative carbon mineralization from lab incubation experiments. Our results indicated that aggregate crushing led on average to 31% extra OC mineralization compared with intact aggregates, which represents 0.65 to 1.01% of soil OC. This result suggests the mineralization of a previously protected pool of labile OC. The amount of de-protected OC by crushing was positively correlated with soil pH and clay content. The crushing effect on OC mineralization depended on the aggregate size and crushing intensity. The intense destruction of aggregates to <0.05 mm had a greater effect than the destruction of aggregates to > 2mm, < 2mm and < 0.25mm, regardless of the initial aggregate size. These results suggest that macroaggregates (>0.25 mm) are less protective than microaggregates (<0.25 mm). Furthermore, the crushing effect is no influenced by the type of agro-ecosystems.