Nationally, there is a steadily increasing emphasis on the improvement of STEM education. This includes the integration of STEM subjects that have been traditionally taught separately, making it critical that prospective STEM educators are equipped to teach using integrated STEM approaches. Connected, an important challenge is providing preservice STEM teachers with experiences in which they can develop an understanding of how to optimize learning through integrated STEM instruction. A potentially effective way to foster this conceptualization is through video analysis of integrated STEM practices. To investigate this possibility, here we present a semester-long study focused on engaging preservice STEM teachers with observing, analyzing, and reflecting about instructional STEM practices through a video-based intervention. Findings suggest that viewing and reflecting on integrated STEM practices may enhance preservice STEM teachers' conceptions of integrated STEM approaches, representing a practical method of preservice STEM teacher professional development.