The Mucor genus, a polyphyletic group pertaining to early diverging lineages of fungi, includes a high number of ubiquitous species. Some species have positive or negative impacts on human activities. Indeed, certain pathogenic Mucor species are a threat for animal and human health and identified more frequently as mycosis causative agents, especially in immunocompromised patients. On the contrary, a small number of Mucor species have been used for centuries in food manufacturing for cheese ripening or Asian fermented food production. Some species are also used as biotechnologically important microorganisms due to their high growth rates, dimorphism (for certain species) and their previously unsuspected potential for secondary metabolite production. Despite all these important roles played by Mucor spp., they have been less investigated than ascomycetous or basidiomycetous species and their taxonomy, metabolism and ecology are less documented when compared to their counterparts in the so-called higher fungi. Nevertheless, research focusing most often on the emblematic Mucor circinelloides species has led to increased knowledge on the biology of this genus, and overall on fungal biology. This is particularly documented for fungal dimorphism or light-induced gene regulation. The aim of this review is to give an overview of the current knowledge on Mucor morphology, taxonomy, ecology and genetics and of its importance regarding human health and industrial applications.