The objective of the study was to measure the impact of personality and other factors on the decision to initiate breastfeeding. Mothers were enrolled (24-96 hours postpartum) and were classified as fully breastfeeding, formula-feeding, or combination-feeding. A semi-structured interview about maternal sociodemographics and attitudes and a standardized personality inventory (NEO-PI-R) were conducted. Eighty-seven mothers completed the study: 50 breastfeeders, 6 combination feeders, and 31 formula feeders. Because of small numbers, combination-feeder mothers (n = 6) were excluded from analyses. Maternal age, marriage, ethnicity, and socioeconomic status were significantly associated with breastfeeding. Breastfeeding and formula-feeding groups differed on 3 personality domains: extraversion (53.3 breastfeeding vs 46.9 formula-feeding, P = .002), openness (51.6 vs 46.2, P = .008), and agreeableness (48.5 vs 41.5, P = .01). In a multiple variable logistic regression model, extraversion (P = .03) and openness (P = .003) remained significant. Sociodemographics, experiential factors, and specific personality characteristics of mother were independently associated with maternal feeding decision.