Background/Aims: Tumor micrometastasis usually occurs at early stage. Therefore, we aimed to investigate the morphology of disseminated tumor cells (DTCs) and its clinical significance in bone marrow (BM) of patients with gastric cancer. Methodology: Forty patients with gastric cancer were enrolled and mononuclear cells were separated from BMs. After labeled by MACS microbeads conjugated with human epithelial antigen (HEA) antibodies, tumor cells were viably enriched twice by MS+/RS+ positive separation column. Parts of the cells from the patients were stained with CK-FITC, DAPI and EB. Then, morphology of the stained tumor cells was observed under fluorescence microscope. Results: Six hundred mid eighty eight CK positive cells in 18 cases (45%) were detected, including 384 (55.8%) medium-sized cells, 102 (14.8%) large-sized cells, 46 (6.7%) stem-ell-like cells, 8 (1.2%) M-phase cells, 84:(12.2%) nuclear debris and 64 (9.3%) non-nuclear debris. The number of tumor cells in BM was significantly correlated with TNM stage (p=0.038), but not with gender, age, histological differentiation and lymph node metastasis. Conclusions: The DTCs in BM of patients with gastric cancer show various morphological characteristics. The existence of these tumor cells suggests a poor prognosis.