The purpose of this study was to investigate the effects of mothers’ psychopathologies and sociodemographic characteristics on exclusive breastfeeding within postpartum 1-1.5 months. In a longitudinal study undertaken in Dr. Zekai Tahir Burak Maternity and Research Hospital between July-October 2006, 657 mothers voluntarily enrolled within 4 to 36 hours postpartum. In the first interview, the mothers completed a questionnaire including maternal, gestational, and neonatal characteristics and a Brief Symptom Inventory (BSI), an instrument used for psychopathological evaluations. Only 46% (n=302) of the mothers were reached by telephone between postpartum 1-1.5 months for the second interview. At 1-1.5 months of age, 64.2% of the infants were exclusively breastfed. Exclusively and partially breastfed infants had similar maternal scores of BSI subscales and indexes. Exclusive breastfeeding rate was lower among infants with low family income, employed mother, planned pregnancy, maternal smoking as well as in infants having health problems at birth and excessive crying. Maternal age, education level, maternal illness/anemia during pregnancy, maternal psychological problems within the last year, birth interval, newborn gender, gestational age, birth weight, and delivery method did not influence exclusive breastfeeding within postpartum 1-1.5 months. Overall, exclusive breastfed infants had less health and breastfeeding problems. Multivariate logistic regression analysis revealed that higher family income, maternal employment, planned pregnancy, excessive crying, health problems during the first three days of life, and breastfeeding problems had negative correlations with exclusive breastfeeding between postpartum 1-1.5 months. Sociodemographic characteristics of the family and mother should be regularly assessed for their influence on exclusive breastfeeding. Anahtar Kelimeler : sadece anne sütü ile beslenme, anne psikopatolojileri, sosyodemografik özellikler, Kısa Semptom Envanteri.