Nurse practitioners (NPs) in Ontario work in a number of settings, including physician-led, interprofessional Family Health Teams (FHTs). However, many aspects of NP practice within the FHTs are unknown. Our study aimed to describe the characteristics of NP practice in FHTs and the relationships between NPs and physicians within this model. This cross-sectional descriptive study analyzed NP service and diagnostic code data collected for every NP patient encounter from 2012 to 2015. Encounter data were linked to health administrative data housed at the Institute for Clinical Evaluative Sciences to allow for comparison with physician service and diagnostic codes. Findings demonstrated that NPs saw patients across all age groups for one to more than five problems per encounter and that NPs handled both acute and episodic care and chronic disease management issues. Patients with chronic conditions had more encounters with physicians than with NPs. In addition, compared to physicians, NPs saw more female than male patients. Our findings provide a snapshot of NP practice in FHTs and may be useful in informing other practice models in Ontario, elsewhere in Canada, and internationally. More evidence is needed, however, to clarify the responsibilities of the NPs in collaborative relationships with physicians and to embed policies that will ensure that NPs work to their full potential. In addition, applying service coding to all health care providers in FHTs could enhance data on interprofessional teams and the individual clinicians that comprise them.