The toxic potential of nevirapine in pregnant women with CD4 count over 250 cells mm3 and the unsatisfactory efficacy of nelfinavir in patients with baseline Viral Load (VL) over 100,000 copies mL1 has prompted the use of Lopinavir/ritonavir (LPV/r) in selected situations. This study aims to assess safety of LPV/r in pregnancy. Medical records from pregnant women receiving LPV/r were retrospectively reviewed. Charts corresponding to twin pregnancy, hypertension and having a lack of data supporting a reliable estimate of Gestational Age (GA) at delivery were excluded. Low Birth Weight (LBW) was defined as less than 2500 g. Pre-Term Delivery (PD), defined as GA at delivery less than 259 days, was estimated using date of Last Menstruation Period (LMP) and obstetrical ultrasound. A total of 64 women were analyzed. LPV/r was used in 46.9% due to virologic failure with other Protease Inhibitors (PIs). LPV/r was used for a mean of 108.8 days. Baseline median CD4+ cell count and HIV-1 RNA were 287 mm^-3 and 31,100 copies mL^-1, respectively and 345 mm^-3 and less than 400 copies mL^-1 at delivery. HIV-1 was not transmitted to any newborn. LBW was observed in 13 (20.3%) and PD in 16 (25%) newborns. Time on LPV/r during pregnancy, maternal age, baseline CD4+ cell count and HIV-1 RNA, GA at initiation of LPV/r, reason for prescribing LPV/r and type of delivery were not associated with PD. Frequencies of LBW and PD were, respectively, 20.3 and 25%. Neither the magnitude nor the timing in pregnancy of LPV/r use was associated with PD.