Preclinical molecular imaging is an emerging field. Improving the ability of scientists to study the molecular basis of human pathology in animals is of the utmost importance for future advances in all fields of human medicine. Moreover, the possibility of developing new imaging techniques or of implementing old ones adapted to the clinic is a significant area. Cardiology, neurology, immunology and oncology have all been studied with preclinical molecular imaging. The functional techniques of photoacoustic imaging (PAT), fluorescence molecular tomography (FMT), positron emission tomography (PET), and single photon emission computed tomography (SPECT) in association with each other or with the ana-tomic reference provided by computed tomography (CT) as well as with anatomic and functional information provided by magnetic resonance (MR) have all been proficiently applied to animal models of human disease. All the above -mentioned imaging techniques have shown their ability to explore the molecular mechanisms involved in animal models of disease. The clinical translatability of most of the techniques motivates the ongoing study of their possible fields of application. The ability to combine two or more techniques allows obtaining as much information as possible on the molecular processes involved in pathologies, reducing the number of animals necessary in each experiment. Merging molecular probes compatible with various imaging technique will further expand the capability to achieve the best results.