The present investigation examines the antimicrobial susceptibility of 85 strains of Neisseria spp, isolated from onco-hematological patients, to various agents used for the treatment of neisserial infections. Of the 85 isolates 13 (15%), 9 (11%), 73 (86%), 2 (2%) and 7 (8%) were resistant to cefotaxime, cefixime, rifampicin, chrolamphenicol and ciprofloxacin, respectively. Of the 85 isolates, 84 (99%) and 83 (98%) showed reduced susceptibility to penicillin and amoxicillin with the minimal inhibitory concentration MIC₅₀ of 6 mg/L. These results indicate that several isolates of Neisseria spp have acquired high resistance levels to various antimicrobial agents, including penicillin, cefotaxime, cefixime, chloramphenicol, rifampicin, and ciprofloxacin.