Aim. To retrospectively analyze the efficacy and safety of ritonavir-boosted saquinavir (SQV) in the perinatal prevention of HIV infection in pregnant women in the Ulyanovsk Region. Materials and methods. The outpatient cards of HIV-positive pregnant women who received ritonavir-boosted SQV in a dose of 1000/100 mg bid in combination with zidovudine or stavudine and lamivudine for the perinatal prevention of HIV infection in 2010-2011 were retrospectively analyzed. The main efficiency criterion was a proportion of children taken off a regular medical check-up in terms of perinatal contact as healthy at 18 months post-birth. The additional criteria (end points) were changes in viral load and CD4 cell count at 4 and 8-12 weeks after initiation of prevention. Results. The analysis included data on 98 HIV-positive pregnant women. The history of HIV infection was 3 years or less in 63.2% of the patients. Stage 3 and 4A HIV infection was stated in 87 and 13% of the women, respectively. Treatment with ritonavir-boosted SQV + 2 nucleotide reverse transcriptase inhibitors was started in 84.8% of the women at 15-28 weeks' gestation and in 12.2% of cases in earlier periods. Four weeks after initiation of highly active antiretroviral therapy, the viral load showed a 1-4 log10 decrease. By that time and at 8-12 weeks, it was undetectable (<500 copies/ml) in 75 (76.5%) and 82 (83.6%) women, respectively. With a decrease in the viral load, CD4 cell count increased by 100-500 per mm3 (mean 160 per mm3). The efficiency of prevention of perinatal HIV transmission was 100%. No serious adverse events were observed. Conclusion. The use of ritonavir-boosted SQV in combination with two nucleotide reverse transcriptase inhibitors is an effective and safe chemoprevention regimen for perinatal HIV transmission in pregnant women.