The study investigated the relationship between entry grades in mathematics and students? performance in business mathematics in colleges of education in North-west zone, Nigeria. Four research questions were raised for the study and four null hypotheses were tested at 0.05 level of significance in order to determine the relationship between the entry grades in mathematics and the students? performance in business mathematics at the federal colleges? education in Nigeria. This study used ex-post facto design. The population was seven hundred and ninety-nine (799); this was made up of students with entry grades in mathematics. The whole population was used for the study and therefore, no sampling was made for the study. The instrument used for data collection was documentary records of students` performance in business mathematics of NCEI in colleges of education. The research questions were answered using mean and standard deviation. The null hypotheses were tested using Pearson Product Moment Correlation (PPMC) at 0.05 level of significance. The findings of the research reveals that there is a positive relationship between students with credit and above entry grades in mathematics and their performance in business mathematics at NCE I. Based on this, conclusion was made that good entry grades in mathematics are the appropriate measures that could improve the performance of the students at the tertiary institutions as well as the provision of one year Pre-NCE Programme for the students with Pass in mathematics 0-level entry grades should enable them to perform better in their business mathematics semester examinations. The research recommended that emphasis should be put on credits entry grades in mathematics for any student admitted to the business education programmes in federal colleges of education in Nigeria.