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; Mage = 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.