The aim of this study was to analyze the value of cytology in differentiation between malignant epithelial tumor metastases and hematologic malignancy. The follow‐up of ten (10) patients who underwent diagnosis and treatment of two malignant diseases, i.e. carcinoma and hematologic malignancy, was performed in the 2000–2005 period. The median of age of our patients was 72 years (range: 49–79). Cytological examination included epithelial tumors, lymph nodes and bone marrow standard Pappenheim and immunocytochemically stained smears. Carcinoma was initially diagnosed in 40% (4/10) patients and hematologic malignancy in 50% (5/10) patients, while both diseases co‐occurred in one patient (1/10). Most of hematologic malignancy cases (4/10) were diagnosed as lymphoma. Multiple myeloma was diagnosed in 3 out of 10 patients (30%). Individual cases of acute myeloblastic leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia were diagnosed in the remaining three patients. Most carcinomas were breast cancer (8/10), while prostate and thyroid gland cancer were diagnosed each in one patient, respectively. Diagn. Cytopathol. 2008;36:710–714. © 2008 Wiley‐Liss, Inc.