Laboratories have been a cornerstone in teaching and learning across multiple scientific disciplines for more than 100 years. At the collegiate level, science laboratories and their corresponding lectures are often offered as separate courses, and students may not be required to concurrently enroll in both. In this study, we provide evidence that enrolling in an introductory laboratory concurrently with the corresponding lecture course enhances learning gains and retention in comparison to students who enroll in the lecture alone. We examined the impact of concurrent versus nonconcurrent enrollment on 9,438 students' withdrawal rates from and final grades in the general chemistry lecture at the University of Michigan at Ann Arbor using multiple linear and binary logistic regression analyses, respectively, at a significance level of 0.05. We found that concurrent enrollment in the lecture and laboratory positively impacts (1) the odds of retention in the lecture by 2.2 times on average and (2) final lecture grades by up to 0.19 grade points on a 4.0 scale for the lowest-scoring students according to university-level mathematics and chemistry placement exam scores. These data provide important results for consideration by curriculum advisors and course planners at universities that do not require concurrent enrollment in general chemistry as well as other science courses. In the face of current budget cuts that threaten to shorten or eliminate laboratory experiences altogether at multiple educational levels, this study demonstrates the value of laboratories in promoting science learning and retention. (Contains 8 tables.)