The purpose of this study was to assess the knowledge, attitude, of breastfeeding working class mothers in Zenith Bank branches in southern part of Nigeria. The study adopted descriptive cross-sectional survey design. The sample size consisted of 195 women who work with Zenith Bank within southern part of Nigeria and have given birth to at least one child. The Statistical Package for Social Sciences version 25.0 was used to analyses the data. Maternal attitude was measured using a five-point Likert scale. Mean scores were calculated for maternal knowledge and attitude. Statistical significance was set at p<0.05. Majority of the mothers (80.45%) were very knowledgeable on exclusive breastfeeding, 89.74% knew that colostrum should be given, while 89.22% knew that breast feeding should be initiated within one hour of giving birth. Most mothers had a positive attitude towards aspects of exclusive breastfeeding: baby should be breastfed exclusively for six months (79.48%); giving colostrum (89.74%); breast feeding should be initiated within one hour (71.79%).. In conclusion, mothers in this study had good knowledge and positive attitude towards exclusive breastfeeding, but the practice of exclusive breastfeeding for six months is lower than WHO recommendation.