Background: As the number of computer science (CS) jobs become increasingly available in this country and computing skills become essential tools for managing all aspects of our personal lives, CS is quickly becoming an essential element of K-12 education and recently, there has been increased attention to bringing computer science to the elementary grades. However, with a schedule that emphasizes literacy and mathematics, and other subjects competing for instructional time, creating opportunities for CS in the elementary school day is challenging. This study aimed to address this problem by investigating the use of problem-based transdisciplinary modules (i.e., "Time4CS" modules) that combined English language arts (ELA), science, and social studies lessons with the Code.org "Fundamentals" CS education program. Results: indicated that teachers who taught Time4CS modules completed more CS lessons than teachers who did not teach the modules. Further, across all classrooms, completing a higher percentage of non-grade level assigned Code.org Fundamentals lessons (i.e., Code.org lessons above or below grade level that were available to teachers, but not required for their particular grade level) was positively associated with students' achievement outcomes on state ELA and mathematics tests. Additionally, higher amounts of interdisciplinary teaching practices were associated with higher student achievement, specifically students' state assessment ELA scores. Conclusions: This study demonstrated that transdisciplinary problem-based modules that integrate the teaching of CS with other subject areas are a feasible way to bring more CS opportunities to younger learners. Moreover, it showed that implementing such modules is linked to more positive student academic achievement outcomes. With attentive revision, the modules featured in this study may be useful tools for elementary schools. These findings have implications for researchers, school district administrators, and those individuals who are in-charge of public policy initiatives seeking ways to bring CS to all elementary school students. Specifically, they highlight that it is possible to make time in the elementary school day for CS, and that there are no negative consequences for core subjects (e.g., ELA and mathematics).