Journal of population and social studies, 2018; 26 (3): 195-206This paper explored gender determined roles and their impact to under-five mortalityin the study area. Across-sectional research design was used to collect data from 160 agro-pastoralist households using a simple random sampling technique.Data were collected in August, 2016in Handeni District, Tanzania mainly througha questionnaire-based survey. Descriptive statistics showed households prevalenceof under-five mortality 12 months prior to the survey for Kibaya, Msomera, Malezi and Kilimilang’ombe villages to be 24.6%, 24.6%, 31.6% and 19.2%, respectively. Binary logistic regression analysis showed that timely household decision, control of household income and equal involvement of household members in the subsistence farming had significant influence on reduction of household under-five mortality. The influence was atβ=-0.071, p = 0.000, odd ratio = 0.931, β= -1.828, p = 0.032, odd ratio = 0.674 and β= -1.013, p = 0.022, odd ration = 0.362respectively.The study findings indicate that women involvement in household decision making and use of household income contribute to the reduction of under-five mortality. It is also the same when subsistence farming is considered as a role for all household members rather than considering it as a women’s role alone. Government, non-governmental organisations and other stakeholders should create awareness campaigns in form of seminars and workshops on gender equality in agro-pastoralist communities.This paper recommends further studies to explore roles of culture on household power dynamics and their implication to under-five mortality.