For countries concerned about equity and access to higher education, providing support services for academically underprepared students is critical to increasing their probabilities of success. Corequisite math courses provide opportunities for underprepared students to develop their basic math skills through simultaneous enrollment in college-level and developmental courses. However, adding the additional developmental course also increases students' academic workload, potentially impeding their progress early in their college journey. Our study explores the effects of being assigned to this additional developmental math class at one of the largest technical colleges in Chile. Few remedial studies have examined the effects of corequisite courses in the technical college context, either in the United States or abroad. Using a regression discontinuity design, we find that for students attending a technical college and scoring close to the cutoff on a standardized mathematics placement exam, being assigned to a corequisite math course increases the grades in their college-level math course and marginally decreases their likelihood of withdrawing during the first semester, compared to students assigned to a single college-level math course. The effects on credits earned and first semester grades are driven by those pursuing less advanced technical degrees.