The objective of this study was to investigate the effect of project monitoring andrncontrolling practice on project success in information network security agency (INSA).rnTo achieve the objectives of the study the researcher adopted both Primary andrnSecondary data sources; Quantitative and Qualitative research approaches andrnDescriptive and Explanatory research design. The target population of the study werern115 employees of the agency who took a role in undertaking commercial softwarerndevelopment projects. Purposive sampling technique was used to select only commercialrnsoftware development projects undertaken in the past five years and a stratified samplingrntechnique was employed to select respondents from different functional teams thus therncommercial software development project always comprises. While The quantitative datarnwas analysed using descriptive, correlation and regression analysis using SPSS versionrn23.0, The qualitative data was analysed, described, and interpreted in the form ofrnstatement. The major findings of the study revealed that there is good project monitoringrnand controlling practice in the organization, yet relatively there is weak project changerncontrol practice. Results also revealed that Pearson correlation between project progressrntracking, project progress reporting, project change control and project documentationrnpractice were strongly positive with project success. Regression results show that Amongrnall the project monitoring and controlling practices, project change control has relativelyrnthe highest influence on the project success and 60.6% of changes in the project successrnattributed to the combined effect of project Progress tracking, project progress reporting,rnproject change control, and project documentation. From this, the study concludes thatrnthe overall project monitoring and controlling practice have a strong impact on projectrnsuccess. This means the practice of project monitoring and controlling with a high levelrnof effectiveness yields a higher level of project success. To be more successful in projects,rnthe study recommends that the organization must focus on enhancing project monitoringrnand controlling practice, especially on project change control areas as they have thernhighest impact on project success, yet they are practiced poorly in the organization.