Bacillus subtilis undergoes two modes of cell division.  During vegetative growth, the bacteria divides by positioning a septum in the middle of the progenitor cell. In contrast, during sporulation B. subtilis divides asymmetrically, with the septum forming in one of the two polar regions of the rod-shaped cell. A key step in determining the position of the new division septum is the polymerization of the tubulin-like FtsZ protein into a ring structure (the Z ring) that serves as a scaffold for  the cytokinetic machinery. During vegetative growth, medial division is favored because of the action of the Min system, a selective inhibitor of Z ring formation which prevents the assembly of the cytokinetic machinery specifically at the cell poles. The Min system is composed of complexes of the MinC and MinD proteins (MinCD) and its spatial selectivity stems from the fact that the MinCD complexes are themselves localized to the bacterial poles. It has been suggested that in the sporulation phase MinCD leaves the polar regions leading to the asymmetric septum formation. Nevertheless, no experimental evidence has been produced to support this hypothesis. The goal of this work was to use live cell microscopy to carry out a detailed investigation of the subcellular location and dynamic behavior of the MinC and MinD proteins during sporulation. To do that, we have constructed B. subtilis strains bearing GFP fusions to either MinC or MinD. Preliminary analysis by fluorescence microscopy suggests that both GFP-MinC and GFP-MinD remain in the polar regions during sporulation. This result implies that a mechanism other than delocalization of the MinCD inhibitor is responsible for asymmetric division during sporulation.