The POTM1-1 gene is abundantly expressed in both vegetative and reproductive organs of potato. We performed in situ hybridization and RNA blotting analysis to investigate the patterns of POTM1-1 gene expression in the flower development and the early tuber development. In the early flowers, POTM1-1 transcripts were accumulated abundantly in the developing reproductive organs, including the placentae of carpels and the pollen sacs of stamens. In contrast, the pattern of POTM1-1 distribution during late flower development was different from that of the early flower development. The POTM1-1 transcripts were abundant in the sepals and petals of late flowers, but were minimally expressed in the stamens and carpel. In the shoot apical meristem of the vegetative organs, transcripts were distributed throughout meristem domes, young leaves, and developing vascular cambium. In the early tuberization, the transcripts were widely distributed in the swollen tips of the stolons. Taken together, the results suggest that POTM1-1 gene expression is temporally and spatially regulated in active growing tissues of both vegetative and floral organs with specific distribution patterns dependent upon the developmental stages of the tissue.