This research writing focuses on The effect of marketing research in product planning process, with a case study of Unilever PLC, Aba, Abia state. This project work is designed to enlighten firms who have not yet understood this very well and those who are still ignorant of this fact that marketing research is inevitable in product planning process. if a firm will succeed, survive and grow in this competitive environment and in this era of marketing concept. This entire project is logically arranged in five chapters one contains the introduction of the company, statement of problem, objectives of the study, research question, research hypothesis, significance of the study and definition of terms, chapter two contains the literature review of selected authors and researchers works, chapter three contains the research methodology, which are the research design, the sources of data, population of study, sampling technique, instrument or method of data analysis and tools used for hypothesis testing. Chapter four contains the presentation and analysis of data collection the discussion of finding and test of hypothesis. Then the chapter five has the summary of findings, conclusion and recommendations, the bibliography and appendix. This work will be beneficial not only to firms in manufacturing industries but also to possible entrepreneurs and lecturers in the higher institution of learning for lecturing students.