To identify the factors associated with the acceptance of tubal ligation after childbirth among HIV-infected patients.A case-control study was conducted from March 1988 to February 1999, at Mexico's National Institute of Perinatology (INPer), in 72 HIV-positive pregnant women. Cases were 49 women who accepted postpartum tubal ligation after childbirth, and controls were 23 women who refused this birth control method. Data collected for each patient were demographic characteristics, sexual and reproductive history, and HIV status. Statistical analysis consisted of descriptive measures, Chi 2 or Fisher's exact test for categorical variables, and Student's t test for continuous variables. Odds ratios (OR) with 95% CI were used to compare groups and potential confounders were assessed by stratified analysis with the Mantel-Haenszel method.The patients' mean age was 25.5 +/- 5.5 years. The median gestation period was 27 weeks (range 7 to 40 weeks); 16 women (22.2%) had no prenatal care visits at INPer. The median time of HIV positivist awareness was 9 months (range 1 to 108). Variables associated with acceptance of tubal ligation were: having a prior childbirth (OR 11.1, 95% CI 3.4 to 36), pregnancy care from 1995 onward (OR 4.7, 95% CI 1.7 to 13.3), and having given birth to an HIV-infected child (OR 4.6, 95% CI 1.05 to 23.1). Stratified analysis showed no modification of the strength of association of these variables with acceptance of tubal ligation.A prior childbirth was the most important predictor of tubal ligation acceptance. The English version of this paper is available at: http://www.insp.mx/salud/index.html.