The presented paper is focused on possibility to evaluate echogenicity grade on ultrasound B-images of the thyroid gland tumor. We use our developed software tool which has been originally designed for analysis of ultrasound B-images in neurology. Currently, the goal of this research is to decide if this software is also useful for different ultrasound B-images, in this case in endocrinology. To evaluate it, the Echo-Index parameter is used. The core principle of the algorithm is based on computing area and computed echogenicity index. The paper has two main parts. The first one is focused on general assessment of the reproducibility of computed Echo-Index between two independent, nonexperienced observers. The second part is concentrated on changes of the echogenicity index (Echo-Index) in the case of malignant tumor and in the case of benign tumor. The general reproducibility is almost perfect, level of agreement based on correlation coefficient is higher than 0.98 and the absolute average error does not exceeds 15 % between two observers. Subsequent analysis between malignant and benign tumor images evinces the Echo-Index is different.