Extensive investments in transport are currently being carried out in Ethiopia. A substantial partrnconsists of railway projects with some underground/tunnel constructions.rnThis research deals with assessment of potential causes of construction delay in tunnels; a casernstudy at Awash-Weldiya railway project which is a new railway line in Ethiopia. The objectivesrnof the research were to: (1) assess the extent of construction delay at tunnels of Awash â€“ Weldiyarnrailway project, (2) identify the key causes of delay and problems encountered during thernconstruction of the tunnels, and (3) to rate the impact of the causes of delay on the constructionrntime of the tunnels.rnQuestionnaire survey together with desk study was used to collect data on tunnel constructionrndelay. A desk study of 6 completed tunnels on the project were investigated and analyzed usingrndescriptive statistics. From the results it was found that 4 out of the 6 tunnels suffered delay. Thernrate of delay on the delayed 4 tunnels ranges from a minimum of 12.84% to 119.41% of thernscheduled amount for each tunnel. The average delay of phase one tunnels of Awash-Weldiyarnrailway project was 38.8%.rnFrom a number of causes of delay in literature, considering the opinion of professionals of thernproject 47 causes were identified and prepared as a questionnaire. A total of 17 questionnairesrnfrom professionals were collected. The findings from the questionnaire shows that Landrnacquisition costs and right of way problems, Delays in payment from client, Late in approvingrndocuments, and Project location were among the top ten causes of delay. The findings also indicaternthat the main problems were right of way, flooding, quality, and health and safety problems.rnBased on impact all the 47 causes were grouped in to three zones in a risk matrix: consequently,rn14 causes had high impact, 31 causes with moderate impact, and 2 causes had minor impact on thernconstruction time of phase one tunnels of Awash â€“ Weldiya railway project.