Job design is defined as specifying the contents or methods of any job in such a way that various requirements of the job holder can be effectively satisfied (Buchanan, 1979). Organizations are always in pursuit of finding ways to enhance their performance. One of the ways is to enhance employee performance by incorporating job designs that contribute to employee motivation, satisfaction and employee performance. The job characteristics necessary for better performance of employees are skill variety, task identity, task significance, autonomy and feedback. The purpose of this study was to determine the effect of job design on employee performance at Ethiopian civil aviation authority Addis Ababa and Bahir Dar office. The study adopted a descriptive research design and Questionnaires were used for primary data collection. The aggregate alpha value in this study was 0.746. The quantitative data in the study was analyzed using descriptive and inferential statistics. Descriptive analysis comprising the means, frequencies, percentages and standard deviations while inferential statistics which included test of hypotheses using stepwise multiple regressions. The statistical package for social sciences (SPSS version 23) was used to conduct the analysis. Tables were used for ease presentation of the analysis. From the findings, task significant, task identity, autonomy and feedback were found to effect on employees performances. The study unveiled the significance of the relationship that exists between Task significant and employee performance with a P value is 0.000. Task identity also found significant at a P value of 0.002 and Feedback found significant at a P value of 0.000. However, skill variety has not significant effect on employee performance the P value of 0.664. Findings from the multiple regression analysis depict, 62.5% variation in employee performance is explained by the organization job design variables. Task significance job design is the most contributing job design traits in the prediction of employee performance with beta value .406(40.6%). The study recommends proper job design helps to increase employee’s performance in Ethiopian civil aviation authority Addis Ababa and Bahir Dar office. Recommendations were made for further research on the Organizational performance and the influence of demographic factors on employee performance