Abstract: Extracting the shape of the gallbladder from an ultrasonography (USG) image is an important step in software supporting medical diagnostics, as it allows superfluous information which is immaterial in the diagnostic process to be eliminated. In this project, several active contour models were used to segment the shape of the gallbladder, both for cases free of lesions, and for those showing specific disease units, namely: lithiasis, polyps, and anatomical changes, such as folds of the gallbladder. The approximate edge of the gallbladder is found by applying one of the active contour models like the membrane and motion equation as well as the gradient vector flow model (GVF-snake). Then, the fragment of the image located outside the identified gallbladder contour is eliminated from the image. The tests carried out showed that the average value of the Dice similarity coefficient for the three active contour models applied reached 81.8%.