Fluconazole – antimycotic belonging to the first generation azoles – is widely used as treatment for invasive candidiasis and candidemia in numerous clinical settings as Neonatal Intensive Care Unit (NICU) and adult Intensive Care Unit (ICU), as well as oncology, onco-hematology and solid organ transplantation. More recently use of antimycotics has spread to medical divisions, where fungal infections represent an emerging problem due to population’s ageing, malnourishment and important comorbidities. Fluconazole is effective against numerous Candida species, particularly against albicans, tropicalis and parapsilosis strains. On the other hand, C. krusei is intrinsically resistant to fluconazole and C. glabrata can be sensitive or resistant in a dose dependent fashion. Epidemiological variability is noteworthy and depends on the geographical location of the institution, the clinical setting, and the frequency and intensity of fluconazole employment for invasive candidiasis. In many ICUs fluconazole sensitive C. albicans is cultured in 50% of positive samples, while the remaining 50% show growth of variably sensitive fungal species, often resistant to fluconazole. Due to increasingly frequent emergence of resistant strains of Candida spp., American guidelines (IDSA) in 2009, and European ones (ESCMID) in 2012, recommended substitution of fluconazole with echinocandines as first line therapy in patients with severe disease, as defined by an APACHE II score greater than 15. Thus fluconazole must be limited to low risk cases, treatment of sensitive strains and de-escalation from echinocandin therapy, after microbiological diagnosis and drug resistance profile characterization.