Tumor-associated macrophages (TAMs) are among the first non-tumoral cells that infiltrate the tumor microenvironment (TME) and encompass up to half of the tumor mass. Extensive research shows that increased TAM density is linked to tumor aggressiveness and poor prognosis. As growing evidence indicates the prominent role of TAMs in tumorigenesis, the development of novel in vivo imaging techniques becomes more important for detailed understanding of the function and activity of endogenous TAMs within the complex TME and for monitoring their response to different therapeutic interventions. Furthermore, efficient imaging tools could provide the opportunity for non-invasive longitudinal assessment of temporal and spatial distribution of TAMs within the tumor. The purpose of this chapter is to provide an overview of the clinical and therapeutic implications of in vivo imaging and targeting of TAMs using different modalities such as magnetic resonance and optical imaging. The current challenges that hinder further development of TAM imaging are also discussed.