The paper examined the impact of maternal age at birth on under-5 death in Nigeria.Secondary data were generated from the 2003 Nigeria Demographic and Health Surveys in examining the relationship between maternal age at birth and under-5 mortality risk. Relationships between variables were tested through bivariate and logistic analyses.Out of 7620 sampled women for the study, almost 60% were less than 30 years old, the median age was 26 years- a youthful population. Analyses of the data revealed a high under-5 mortality rate (45.4%), a general high home delivery (62.4%) among Nigerian women, which dictates a low rate at which assistance by health professional is being sought during childbirth . Furthermore, mothers' median age at first birth was less than 19, while under-5 death was significantly pronounced among younger (less than 20 years) mothers and older women (above 35 years) (p<0.05). Maternal education which was significantly low among younger mothers was a predictor of under-5 mortality.Under -5 mortality is still high especially among younger mothers. Thus resolving this challenge in Nigeria will be inadequate if early childbearing issues are not addressed using a tailored framework alongside with the need to improve maternal education in Nigeria.