Breastfeeding is an unequalled way of providing ideal food for the infants. The benefits of breastfeeding practices to infants and mothers are well documented. However, information on breastfeeding practices and its effect on body mass index (BMI) of mothers are scarce, particularly in Ekiti State of Nigeria. Therefore, the present study is designed to assess breastfeeding practices and its association with BMI of mothers. A descriptive and cross-sectional study was conducted among breastfeeding mothers that attended postnatal clinic of the state specialist hospitals and maternity centers in the study location. The specialist hospital and two-third of the nine maternity centers were purposively selected because of their health facilities and personnel. The mother-child pairs (200 respondents) were randomly selected from the study locations. Information on demographic characteristic, socio-economic parameters, nutritional knowledge of breastfeeding and dietary intakes of mothers were collected using questionnaires. BMI of mothers was determined as described by World Health Organization. Age distribution of mothers was between 25-34 years; and almost half of respondents had good educational background and were engaged in different occupations. The respondent monthly income ranged between = N = 3500 - 26000 ($26.92 - $200); and their dietary intakes varied between starchy and protein-based food. The result also showed that the respondent consumed enough nutrients to meet up the recommended daily allowance for protein, carbohydrate, fat, zinc, magnesium, sodium and phosphorous requirements. The BMI classifications showed that over three-fifth of respondents were normal, while the remaining were underweight (6%) and overweight/obese (26.5%). Also, large proportion of respondents engaged in exclusive breastfeeding and with good knowledge of breastfeeding practices. Statistically, exclusive breastfeeding practices had no correlation between the BMI and frequency of breastfeeding. The study, therefore, concluded that mothers had good knowledge of breastfeeding practice; and that there was no association between breastfeeding practices and BMI.