In Ethiopia it is common problem to observe time performance problem in almost all road construction projects either completed in the previous years or currently progressing and the situations are still showing little or no improvements. The factors that result in poor time performance has been dealt by different professional, researchers largely on the magnitude of their effect of various nation construction projects. The aim of this thesis is to identify and evaluate the main factors affecting the time performance of road construction projects particularly on new and upgrading projects which have been executed or being progressing under Ethiopian Roads Authority by local contractors. In the literature review part of this research factors affecting the time performance have been identified and local factors have been added from local experts’ recommendations through an interview. About 22 completed and/or on progress under the ERA, RSDP III and IV were sampled for analysis of their time performance with the identified causing factors. A questionnaire survey was conducted on the identified factors under major groups of planning, management, financial, technical, material equipment and labor for the sampled projects. In addition, a case study has been conducted on selected four projects to identify factors that affect the time performance on the specific cases. As per the weighted rank of the respondent, financial related problems, improper utilization of advance payment followed by financial constraint for construction material and spare parts have been agreed as very important factors that affect the time performance. Through the course of the case study respondents have suggested that ERA shall assist in financing the project with setting rules and regulation to tackle the improper advance payment utilization. In line with this the researcher has learnt that ERA, the client pre-financed projects under the case study by taking into account the seriousness of the issue. On the other hand, poor management which is manifested as unrealistic resource allocation in the planning period and poor site coordination of available resource during the construction period was ranked as the preceding factor. Finally, selected respondents have been interviewed for their recommendation to curb the ranked factors and to minimize their effect for the upcoming projects.