The aim of the current study was to investigate whether infant temperament determines first-time mother’s self-efficacy, perceived stress level and general well-being. Further, the research was trying to find if mothers who breast-fed their infants perceived lower level of stress than mother’s who bottle –fed their infants. This study was correlational and descriptive in nature and was based on quantitative cross-sectional design. A questionnaire combining Infant Characteristics Scale, Maternal Self Efficacy Scale, Perceived Stress Level Scale, General Health Scale and demographic questions (age, education, marital status, employment status, and the method of how the baby was fed ) was created as the on line survey. 233 mothers participated in the on line survey. The results indicated that the more difficult the infant the lower maternal self-efficacy, the higher perceived stress level and the lower stress levels than mothers who bottle-fed their infants. Findings from this study indicate the importance of supporting first-time mothers in their transition into parenthood. Keywords: infant temperament, self- efficacy, stress, well-being.