The promotion of positive attitudes towards science is an important goal of science education. This research aimed to identify students' attitudes towards science and whether their participation within a citizen science project has contributed to positive attitudinal changes. So, an attitudinal scale was developed, validated, and applied (as a pre and post-test) to 574 students aged between 12 and 14 years old. Positive attitudes towards science were recorded from the outset among children of both groups. Students' participation within the experimental group enhanced relevant positive attitudinal changes at the level of the critical analysis dimension, related to the perception of skills development such as questioning or critical thinking. Furthermore, positive attitudinal changes were achieved within the affinity dimension, related to perceived self-efficacy and appreciation of science and science classes. Positive attitudinal changes towards science among students indicate that citizen science contributes to enhance affective and attitudinal domains of their scientific literacy.