The today challenge which causes primary school children not to complete the cycle of seven years of primary education is child labour. Although efforts have been made by different organs to fight against child labour, but there seem to be difficult, as a result completion rate of standard seven pupils is decreasing time to time. Therefore the purpose of this study was to determine the impact of child labour on primary school completion. The study employed exploratory design where by quantitative data was collected by use of a questionnaire that was administered to 54 pupils. In addition qualitative data was collected through an interview conducted among six (6) heads of schools, one (1) district education officer, six (6) school committee representatives, six (6) ward education coordinator and thirty five (35) street children. The purposive, systematic and snowball sampling techniques were used to select the respondents. The data was analyzed using a computer programme, the statistical package for social sciences (SPSS) version 16.0. An analysis of the findings indicated that there is big relationship between child labour and primary school completion rate also there is relationship between child labour and absenteeism. Again the findings showed that those pupils from poor families are mostly affected by child labour compared to the children from rich families. It was recommended that the government should establish a strong relationship with different partners to protect children through establishment of different programs, policies and to enact and enforce different laws which will protect children from labouring