BACKGROUND: The main mechanism of drug hypersensitivity to non-steroidal anti-inflammatory drugs is associated with inhibition of cyclooxygenase type 1, which leads to cross-hypersensitivity reactions to non-steroidal anti-inflammatory drugs from various subgroups of different chemical structures. Clinically, cross-hypersensitivity usually manifests in the form of urticaria and/or angioedema. AIM: To characterize a group of patients with cross-hypersensitivity to non-steroidal anti-inflammatory drugs manifesting as urticaria / angioedema / anaphylaxis. MATERIALS AND METHODS: To achieve this aim a prospective single-center study was conducted. Patients with a presumptive diagnosis of drug hypersensitivity to non-steroidal anti-inflammatory drugs (n=307) were consulted. A group of patients (n=237) with high probability of such reactions was identified, of which cross-hypersensitivity manifested as urticaria / angioedema / anaphylaxis was observed in 127 patients. This group was divided into 2 phenotypes: a group with concomitant chronic urticaria (n=67) and without it (n=60). We assessed demographic data, drug triggers, clinical manifestations, concomitant atopy, and compared these indicators between both groups. Selected patients underwent a drug provocation test with selective or predominantly selective non-steroidal anti-inflammatory drugs and paracetamol. RESULTS: Cross-hypersensitivity reactions manifested as urticaria / angioedema / anaphylaxis is the most common phenotype of immediate-type drug cross-hypersensitivity reactions to non-steroidal anti-inflammatory drugs (75.6%). Women develop this condition 2.5 times more frequently than men, and are more likely to develop cross-drug hypersensitivity with concomitant chronic urticaria with the onset of approximately 16 years later than men. Mild manifestations of cross-hypersensitivity (urticaria/angioedema) develop more frequently than severe ones (anaphylaxis). Angioedema in children, urticaria in adults with concomitant chronic urticaria and angioedema in adults without concomitant chronic urticaria are it's main manifestations. The most frequent non-steroidal anti-inflammatory drugs triggers are metamizole, acetylsalicylic acid and propionic acid derivatives. Non-steroidal anti-inflammatory drugs with the lowest risk of developing drug hypersensitivity are coxibs, paracetamol, and to a lesser extent ― meloxicam, nimesulide. CONCLUSION: The data obtained allowed us to expand our understanding of cross-hypersensitivity reactions to non-steroidal anti-inflammatory drugs presenting as urticaria/angioedema or anaphylaxis. Selective cyclooxygenase type 2 inhibitors and paracetamol are drugs with the highest safety profile.