The incidence of focal lesions in the spleen is 3.2–4.2% per 100,000 population. Spleen cysts are rare (incidence 0.75 per 100,000). These are single or multiple, thin- and smooth-walled cavities filled with a transparent liquid. Distinguish between primary (or true) cysts, lined with epithelium, and secondary (or false), devoid of epithelial lining. Among the primary cysts, there are congenital cysts formed in the embryonic period due to the migration of peritoneal cells into the spleen tissue, dermoid and epidermoid cysts. A special group of primary cysts are parasitic cysts. Cystic tumors of the spleen include lymphangioma and lymphoma.The main difficulties in the diagnosis and differential diagnosis of cysts and cystic tumors of the spleen are associated with the rarity of this pathology and, as a consequence, a small number of works, including a significant number of the cases. However, in those works where a large number of the cases are described, most often this is one morphological form and an analysis of its various characteristics.Purpose. Based on the analysis of our own examination data of a significant number of patients with cysts and cystic tumors of the spleen, to assess the possibility of differential diagnosis of individual morphological forms according to ultrasound data.Materials and methods. 323 patients with cysts and cystic tumors of the spleen from 15 to 77 years old (men – 105 (32.5%); women – 218 (67.5%) were treated at A.V. Vishnevsky National Medical Research Center of Surgery for the period from 1980 to 2020. All patients underwent ultrasound during examination. Surgical treatment was carried out in various ways – (85.1%), when making a preoperative diagnosis of an uncomplicated spleen cyst of small size, dynamic observation was carried out (verification by puncture biopsy data).Results. Morphological verification of cysts and cystic tumors of the spleen was presented as follows (taking into account possible difficulties in identifying the epithelial lining): true cyst – 182 (56.4%); dermoid cyst – 3 (0.9%) (malignant – in 1 case); pseudocyst – 16 (5.0%); pancreatogenic – 34 (10.5%); echinococcus – 52 (16.1%); lymphangioma – 24 (7.4%); lymphoma – 10 (3.1%); ovarian cancer metastasis – 2 (0.6%). The article describes the ultrasound signs of the above forms of the lesions with an emphasis on the complexity of diagnosis.Conclusions. Primary and parasitic spleen cysts are well differentiated according to ultrasound; false cysts of the spleen, depending on the cause of their occurrence, can create difficulties in their identification and differentiation (they require careful dynamic control); cystic tumors of the spleen should be differentiated from malignant tumors and metastases of a cystic structure, as a result of which such vigilance should always be present when they are detected.