A study was conducted to determine the effect of synthetic mulch on the diversity and abundance of carabid beetles in an organic blueberry crop. The treatments consisted of plastic mulch, plastic mulch combined with pine needles, pine needles only and bare soil as control. Beetles were captured using pitfall traps. The number of individuals collected was greater in the treatment consisting of mesh and pine needles and in bare soil, whereas the mesh treatment alone presented the lowest values. Species richness showed no differences between treatments. Although there were density differences among the treatments, further studies are needed in order to establish the preference of these insects for any particular groundcover more clearly. Nevertheless, the results suggest that the incorporation of vegetal material as mulch in the holes left open in the mesh for the plant may improve the capacity of synthetic covers to harbor carabid beetles and hence improve the biological control of pests, particularly in organic crops.