Objective: To evaluate the relationship between caries and malocclusion in the early and late mixed dentition in a population of children of Chinese migrant workers in Shanghai. Methods: Dental charts were obtained for 646 children in the mixed dentition, aged between 6 and 13 years old. The decayed, missing, and filled teeth (DMFT) index and interproximal tooth structure lost due to caries (ITSLC) were evaluated. Results: In the early mixed dentition, overbite was more likely to be ideal in subjects with DMFT > 0. In the late mixed dentition, crowding in both arches was greater in subjects with DMFT > 0. In the total sample, crowding in the lower arch only was greater in subjects with DMFT > 0. In the early mixed dentition, upper crowding was lower in subjects with ITSLC in the upper arch and in both arches and the rate of anterior crossbite was higher in subjects with ITSLC in the upper arch. In the late mixed dentition, overjet was more likely to be ideal in subjects with ITSLC in the upper arch and upper crowding was greater in subjects with ITSLC in both arches. In the total sample, overjet was more likely to be ideal in subjects with ITSLC in the upper arch and lower crowding was greater in subjects with ITSLC in both arches. Conclusion: A relationship exists between caries and malocclusion, and between ITSLC and malocclusion, and some relationships may change with dental age. Keywords: Dental caries, DMFT, early mixed dentition, late mixed dentition, malocclusion