A study was conducted to quantify the effectiveness of concept maps in learning physics in engineering degrees. The following research question was posed: What was the difference in learning results from the use of concept maps to study a particular topic in an engineering course? The study design was quasi-experimental and used a post-test as a measuring instrument. The sample included 114 university students from the School of Industrial Engineering who were divided into two equivalent homogeneous groups of 57 students each. The amount of learning attained by the students in each group was compared, with the independent variable being the teaching method; the experimental group (E.G.) used concept maps, while the control group (C.G.) did not. We performed a crossover study with the two groups of students, with one group acting as the E.G. for the topic of optical fibers and as the C.G. for the topic of the fundamental particles of matter and vice versa for the other group. For each of the two topics studied, the evaluation instrument was a test of 100 dichotomous items. The resulting data were subjected to a comparative statistical analysis, which revealed a significant difference in the amount of learning attained by the E.G. students as compared with the C.G. students. The results allow us to state that for the use of concept maps, the average increment in the E.G. students' learning was greater than 19 percentage points.