Introduction. The occurrence of malignant lymphoma (ML) among patients with malignant orbital tumors ranges between 10 and 37.3% making early diagnosis clarification crucial for timely treatment. Purpose — to study clinical features of ML with consideration of its morphological type and localization in the orbit. Material and methods. Clinical picture of primary malignant orbital lymphoma of 34 patients (36 orbits) was examined retrospectively with consideration of the tumor’s morphotype. Median observation time was 6 years. Patients aged between 34 and 84 years, female to male ratio was 1.27:1. Results. The final diagnoses were: small cell MALT-type ML (23 patients), large cell B-lymphoma (5 patients), diffuse malignant lymphoma (5 patients), T-cell lymphoma (1 female patient). Systemic changes developed in 29.41% of cases after 6.7 years on average. 23.53% of patients has died. Clinical signs of MALT-type ML were described with consideration of tumor’s localization in the orbit, and clinical features of B-cell, large cell, diffuse and T-cell lymphoma were shown. Signs helping differentiate ML from false tumor, composite tear gland tumor and malignant orbital tumor were established. Conclusions. Despite the higher prevalence of malignant MALT-type lymphoma, primary malignant orbital lymphoma is characterized by unfavorable vital prognosis: in a third of all cases, signs of systemic lesion develop in 6.7 years on average. Clinical picture of MALT-type ML is defined by tumor’s localization in the orbit. Recurrence of MALT-type ML after combined treatment (surgical, radiotherapy, polychemotherapy) happens in every fourth case among patients with tumor primarily localized in the orbital cellular tissues or in the tear gland. Describing clinical features of primary malignant orbital lymphoma allows faster diagnosis clarification reducing the number of orbital diseases that require differential diagnositcs.