A positive attitude correlates to successful learning; while a negative attitude leads to poor learning. The present study aimed to compare the pre-service biology teachers’ attitudes towards learning biology and assessing their attitudinal change before and after being taught by resource-based instructions (RBI) in Rwanda. A survey-research design was used, in combination with a quasi-experimental control group, and the equivalent time-series designs. Pre-service biology teachers were taught at a public university in three separate groups, with one control group and two experimental groups. Each group received a pre-attitude and a post-attitude assessment. In contrast, at a private university, they were taught as a single group, in a series of instructions, starting with the lecture method, followed by animation-based instruction and small- group laboratory activities, in which at each stage, the pre-service biology teachers received the same assessment. The biology Attitudinal Scale showed a Cronbach alpha reliability of 0.625 before its use. The data were analyzed quantitatively; and the results revealed no statistically significant difference between the public and the private pre-service teachers’ attitudes before learning microbiology. After the teaching interventions, the results revealed that both the traditional and the resource-based instructions improved the pre-service biology teachers’ attitudes towards learning biology, as a result of their improved maturity and their anticipated future teaching career.