Postpartum maternal and neonatal readmissions in the period shortly following birth are indicators of serious morbidity. We compared the risk of postpartum maternal and neonatal hospitalizations in women living with and without HIV in Ontario, Canada. We conducted a population-based study of pregnancies in Ontario between April 1, 2002 and March 31, 2011 using Ontario's administrative health care databases. Generalized estimating equations were used to derive adjusted odds ratios (aORs) and 95% confidence intervals (CI) for the association of HIV infection with postpartum maternal hospitalizations within 30 days of hospital discharge and neonatal hospitalizations within 30 and 60 days of hospital discharge. Between 2002/2003 and 2010/2011, 1,133,505 pregnancies were available for analysis, of which 634 (0.06%) were to women living with HIV. The proportion of postpartum maternal hospitalizations (2.8% versus 1.1%; odds ratio 2.53; 95% CI 1.57 to 4.07) was higher among women with HIV. The multivariable adjusted odds ratio was 1.54 (95% CI 0.93 to 2.55). The proportions of neonates hospitalized within 30 (2.6% versus 3.7%; aOR 0.68, 95% CI 0.42 to 1.10) and 60 days (4.9% versus 4.9%; aOR 0.86, 95% CI 0.60 to 1.24) of discharge were similar among infants born to women with and without HIV. Women living with HIV are at a higher risk of postpartum maternal hospitalizations than women not living with HIV. The effect of HIV infection was attenuated by multivariable adjustment, suggesting that sociodemographic or health care factors are responsible for much of the difference in outcomes.