The current study investigated science identity development among Latinx university students selected for a critical race theory (CRT)-informed undergraduate research experience. Twenty students (12 female, 8 male; M[subscript age] = 22.00; SD = 2.77) enrolled in biomedical-related majors at a 4-year university responded to open-ended questions regarding their identity as scientists at 2 weeks, 6 months, and 18 months after they began the program. Results illustrated a steady increase in the number of students identifying as scientists over 18 months. At 2 weeks into the program, only 35% of Latinx students felt like a scientist. At 6 months, 45% of Latinx students identified as a scientist. At 18 months, 70% of Latinx students reported feeling like a scientist. Results also revealed variation in science identity trajectories, with four trajectories viewed in the data: (1) "consistent or fast achievement," (2) "gradual achievement," (3) "achievement adjustment," and (4) "never reach achievement." The majority of students demonstrated a trajectory in which they reached science identity achievement (the feeling that they are "a scientist"). Our results provide evidence of the positive, longitudinal impact that a CRT-informed curriculum has on the science identity development of Latinx students. Implications surrounding future research and strategies to facilitate long-term Latinx student participation in the biomedical sciences are discussed.