The department of immigration makes decisions in the course of discharging their mandate some of which are contested by those seeking services from the department. The post-work permit verification period has seen an astronomical rise in such contested decisions. Little is known about the determinants of these contested decisions. This research focused on the determinants of contested decisions in government departments in Kenya. There was need to understand the factors that influence the decisions which lead to applicants seeking appellate measures to reverse these decisions. The research was guided by the following research objectives: Examine how fast decision-making at Kenya Immigration Department (KID) affects the efficient handling of contested decisions at the department, determine the extent to which top management influence the appeal process of contested decisions at KID, establish the extent to which knowledge on the provisions of immigration laws affect the efficient handling of contested decisions at the department and to find out how staff perception on contested decisions affect the efficient and effective handling of the contested decisions at KID. A number of theories were used in this study including: conventional migration theories; and new economics of labor migration theory. The study used descriptive research design. The target population therefore was the KID employees from the Work permits, Kenyanization and foreign national registration section. The employees were selected through stratified random sampling from the section. The sample sizes therefore consisted of a total of 80 employees. The researcher constructed closed and open - ended questionnaires, which were administered to the employee selected that were a representation of the study area. The interview schedule designed was administered to top management at the work permits, Kenyanization and foreign national registration section. The research data was analyzed using inferential statistics. This was done using the Statistical Package for Social Sciences. Data presentation was done with the help of tables, pie charts and frequency graphs. The outcome of this study was to establish what determines contested decisions in government departments in Kenya with reference to KID.