Lecture is a common method used in college teaching. Various researches comparing lecture and more active methods in relation to students’ performance presented mixed views on the effectiveness of the lecture. This research aimed to compare the traditional lecture and self-regulating learning method in relation to students’ achievement in Biological Science. The study used quasi-experimental method using non-equivalent group pretest-posttest design. Two intact classes were used with 39 students in each class. A total of 78 first year students were included in the study. The two groups were randomly assigned to the two teaching methods. One group was taught through lecture while the other group through self-regulated learning (SRL) method. Comparability of the students was based on their pretest scores in Biological Science. The study was conducted with an observer. Teacher-made achievement test, course teaching manual, and course reader were used in the study. Results revealed that both lecture and SRL methods increased students’ achievement in Biological Science. However, students in the traditional method obtained higher mean pretest, posttest, and mean gain scores than students exposed to SRL method. Lecture as a teaching method should not be entirely replaced but also integrated with other methods whenever it is appropriate.