The study evaluated the Effect of organisational structure on the performance of food and beverage of manufacturing firms in Enugu State. A study of Aqua Ralpha Investment Limited, 9th mile, Enugu. The specific objectives of the study are: examine the effect of job design on the profitability; evaluate the effect of organization hierarchy on the output and ascertain the effect of job grouping on the operational safety of food and beverage manufacturing firms in Enugu state. The study used the survey approach and stratified random sampling. The primary source was the administration of questionnaire. The population of the study was 302 employees. The whole population was used due to small number. 286 respondents returned the questionnaire and accurately filled. That gave 95 percent response rate. The validity of the instrument was tested using content analysis and the result was good. The reliability was tested using the Pearson correlation coefficient (r). It gave a reliability co-efficient of 0.86 which was also good. Data was presented using tables, percentages, mean score and standard deviation using Sprint Likert Scale. The hypotheses were analyzed using Z – test statistics tool. The findings indicated that Job design had significant positive effect on the profitability; Z (95, n = 286), 6.150 < 7.983,p. <.05.Organisation hierarchy had significant positive effect on the output Z(95, n = 286), 7.273 < 9.491, p. <.05 and Job grouping had significant positive effect on the operational safety of food and beverage manufacturing firms in Enugu state Z(95, n = 286), 6.268 < 7.983, p. <.05. The study concluded that Job design, Organisation hierarchy, Job grouping and Authority designation had significant positive effect on the profitability, output, and operational safety sales volume of food and beverage manufacturing firms in Enugu state. The study recommended among others that to improve job satisfaction, through-put, quality and reduce employee problems (e.g., grievances, absenteeism) the organizations should have job design.