Forty-one mammary gland tumors from twenty eight bitches were used for the study. Ultrasonographic examinations of tumor masses were performed before surgical excision and a quadratic region-of-interest (ROI) was chosen randomly on B-mode tumor images for the echotexture analyses. All tumors were evaluated histopathologically after surgery. Contrast (CONT), Mean Gradient (MG), Mean Value (MV), Homogeneity (HOM), Entropy (ENTR) and Gray Value (GV) parameters were used for the texture analyses of ultrasonographic images. Ultrasonographic image characteristics were additionally evaluated by the following macroscopic patterns: tumor shape, invasion of tumor to surrounding tissue, tumor border sharpness, echogenicity of tumor, hyperechogenic artifact, anechogenic artifact, and shadow around tumor. After B-mode ultrasonographic examination, Pulsatility Index (PI), Resistive Index (RI), Peak Systolic Flow Velocity (Vmax) and Number of Color Pixel (CP) parameters were evaluated by means of color Doppler sonography. Statistical analysis of the HOM and GV parameters indicated that there was a significant difference between benign (3.10 and 1.14) and malignant tumors (1.54 and 0.57; P< 0.01). Besides, a significant difference was found between images of Malignant-Mixed Tumors (MMT) and Benign-Mixed Tumors (BMT) with regard to CONT and HOM (p< 0.001). In addition, MV was significantly higher in malignant tumors in comparison to the benign cases (P< 0.05). A significant negative correlation was found between tumor size and MV in malignant tumor and adenocarcinoma cases (-0.991/P< 0.05; -0.999/P< 0.01, respectively). On the other hand, there was a positive correlation between tumor size and GV (0.961/P< 0.05) in malignant tumors.