Promotion policies increase morale, productivity and employment satisfaction, and to decrease turnover by rewarding employees who possess the desire, commitment and qualifications to advance within the organization. In addition to delivering value to customers and increasing the wealth of shareholders or owners, state owned enterprises must provide satisfying working environment for employees. This study sought to determine the influence of organizational internal environment on service delivery in the civil service in Kenya with special focus on of Immigration Department Headquarters. Survey research design was used in this study because it does not involve manipulation of variables under investigation but seeks to establish the status of the phenomena. The target population of the study was 150 employees working in the immigration department. The study sampled employees of immigration department in Kenya. Proportionate stratified random sampling technique was used to select 50 staffs working with Immigration Department at the Headquarters. Questionnaires were used to collect data for this study. A letter was written to the management of Immigration Department. Data was coded and analyzed using the Statistical Package for Social Sciences (SPSS) software. Descriptive statistics that include frequencies and percentages was used to organize and summarize the data. Tables and bar charts were drawn to present the analyzed data. This is because tables, bar charts, frequencies, and percentages are important statistical methods of organizing and summarizing raw data into a meaningful way for the ease of interpretation. Regression analysis was used to establish the relationship between organizational internal environment and the variables of the study. From the finding, it was revealed that a unit increase in organization politics would lead to an increase in the service delivery in the civil service in Kenya, thus the study concludes that organization politics had positive effects on service delivery in the civil service in Kenya. The study also established that when decision-makers communicate a justification for the decision reached and the decision-maker is considered sincere, participants view the process as fair therefore the study concludes that increased organization justice had a positive effects on service delivery in the civil service in Kenya. When high procedural justice in promotion decisions exists, employees are more likely to experience satisfaction with organizational outcomes thus the study concludes that transparency when making promotion decisions had a positive effect on service delivery in the civil service in Kenya The organization structure should be flexible enough to respond quickly to change, challenge and uncertainty the study concludes that flexible organizational structures had a positive effect on service delivery in the civil service in Kenya In order to improve service delivery in public sector, the study recommends that the Government should put in place policies which shall fairly and equitably responding to employees needs by encouraging participation in decision and policy-making, there is need to encourage professional ethics by ensuring that all promotions are accorder in regard to laid government policies as this encouraged morale to civil servants, There is need to create flexible government structures, this will allow the government officers to respond immediately whenever administrative challenges may arise. There is need to keep right balance between organizational policies by encouraging communication and Listening to employee demands as will help in strategizing on effective ways to deals with their complains.