At the end of the bone-forming phase, osteoblasts can have one of three major fates: (1) become embedded in the bone matrix as osteocytes, (2) cover inactive bone surfaces as bone lining cells, or (3) undergo apoptosis. It is also notable that osteoblasts may transdifferentiate into adipocytes in some situations. Thus, osteoblasts appear to comprise a heterogeneous cell population that may underlie the diversity in transcriptional profiles. To test this hypothesis and its biological implications, we generated transgenic mice expressing Venus under the control of the 2.3 kb Col1a1 promoter. Venus-positive (Venus⁺) cells were isolated from newborn calvariae using sequential digestion with collagenase and EDTA, and subjected to single cell RNA-sequencing. Unsupervised hierarchical clustering demonstrated transcriptional heterogeneity in Venus⁺ cells and categorized them into two major clusters, based on similarities in transcriptomes. Between these two clusters, 145 transcripts were differentially expressed; e.g., mature osteoblast markers and bone marrow stromal cells/osteoprogenitor markers, including Cd34 and Cxcl12. Notably, a large number of Venus⁺ cells retained transcripts involved in adipogenesis, such as the pro-adipogenic factors Klf4, Cebpb and Ebf1, and repressors of adipogenesis, Klf2 and Klf3. Some of these cells also expressed the adipogenic master transcription factors, Pparg and Cebpa. When cultured in osteogenic medium, almost all Venus⁺ cells showed nuclear staining of RUNX2, and some of them showed cytoplasmic staining of PPARγ. A few cells showed double nuclear positive for RUNX2 and PPARγ. In the presence of rosiglitazone, a synthetic agonist of PPARγ, over half of cells failed to be stained with RUNX2, while 20% of them exhibited nuclear staining of PPARγ with accumulations of PERILIPIN-positive lipid droplets. These results suggest that Venus⁺ osteoblasts comprise a heterogeneous population and that some of them retain adipogenic potential.