This study evaluated the influence of crop roots, residues, and zero-tillage management on soil structure in central Mexico. The experiment compared maize and wheat monocultures with and without crop residues under zero-tillage. Results showed that wheat roots favored pore formation more than maize roots. Keeping crop residues on the soil surface was also important for developing soil structure, in addition to root effects. Overall, the combination of crop rotation and residue retention under zero-tillage best improved the total porosity and aggregation of the soil.