Abstract: Context/Background: Under-age marital birth is high in northern Nigeria. We explore the association between under-age marital childbirth and child health indicators in north-west Nigeria. Data source and Methods: Analysing NDHS 2013 data of 9,011 currently married women in northwest Nigeria, with at least a childbirth in the 5 years preceding the survey, we explored the implications of maternal age at first birth for child health outcomes (anthropometric measures and child survival). Results: The lowest age at birth in the region was |2 years. Binary logistics regression shows that odds of child survival was highest among mothers aged 18 years and above at first childbirth by 52% (Cl: 1.17-1.97; p-value < 0.01). Finding suggests that poor child anthropometric outcomes is not associated with under-age childbirth but other factors such as women education and wealth status in the study area. Conclusion: Early childbirth prevention interventions aimed at abrogating child marriages and promoting girl child education are needed in the region. Keywords: Child health; under-age birth; child marriage; girl child education; North-west Nigeria; NDHS