This study investigated the impact of computer mediated systems teaching approach (CMSTA), used to teach mathematics to Nigerian Polytechnic engineering students, on the students' mathematics performance, attitude and anxiety. Specifically, the study determined whether the mean mathematics performance scores, attitude towards mathematics dispositions and mathematics anxiety levels of (a) experimental and control groups differed significantly and (b) experimental group differed significantly gender wise. Six research questions and six null hypotheses were formulated. The experimental group were taught mathematics using the CMSTA while the control group were taught with the conventional teaching approach (CTA) for 12 weeks. 485 subjects, with 274 and 211 in the experimental and control groups respectively, were used. Three instruments, Mathematics Performance Tests (MPTs), Attitude Towards Mathematics Inventory (ATMI) and Mathematics Anxiety Rating Scale (MARS), were used to gather data which were analysed using descriptive and inferential statistics. Hypothesis testing was done at the 95% level of confidence. Significant differences were found between (a) the mathematics performance levels, attitude towards mathematics dispositions and mathematics anxiety levels of the experimental and control groups (b) the mathematics performances of male and female students in the experimental group. However, significant differences were not found between the attitude towards mathematics dispositions and mathematics anxiety levels of the male and female students in the experimental group. Conclusion reached was that the treatment has enhanced the subjects' mathematics performance, fostered their attitude towards mathematics positively and lowered their mathematics anxiety. Consequently, it was recommended amongst others that the CMSTA should be adopted or adapted widely by mathematics teachers/lecturers in Nigerian Polytechnics in particular and other tertiary institutions in general. The contributions and implications of the study, areas for further studies as well as limitations of the study were also stated.