The study investigated the Effects of Field Trip and Discovery Methods on Senior Secondary School Students’ Achievement in Biology in Makurdi Local Government of Benue State. Eight specific objectives, eight research questions were formulated; eight hypotheses were tested at 0.05 level of significance to guide the study. Quasi-experimental design of the non-randomized pre-test post-test control group was used. The sample was made up of 205 SSI students from five senior secondary schools in Makurdi Local Government Area of Benue State. A multistage sampling technique was adopted to draw the sample. The instruments- Biology Achievement Test (BAT) and Biology Retention Test (BRT) were used for data collection and the reliability of BAT was 0.77 using Kuder Richardson formula (KR20. The research questions were answered using mean and standard deviations while the hypotheses were tested at 0.05 level of significance using Analysis of Covariance (ANCOVA). The result showed that the Field Trip and Discovery methods enhanced students’ achievement in Biology. There was no significant difference between male and female students’ achievement and retention in Biology. Based on the findings of the study, secondary school Biology teachers were recommended to adopt these methods in teaching. Suggestions were also made that the methods should be used for other topics that students may find difficulties in the senior secondary schools.