Invasive fungal infections are important causes of morbidity and mortality particularly in high-risk patients. Recognizing such infections is often difficult because of non-specific symptoms and clinical signs. Timely diagnosis is also a challenge due to difficulty in obtaining adequate volume of samples, need for anaesthesia to perform certain diagnostic procedures, and insufficient data and experience related to fungal biomarkers and molecular detection tests. This results in widespread use of empiric broad spectrum antifungal agents with the consequent emergence of drug-resistant strains. This review focusses on the definition, clinical and microbial profile and diagnostic modalities for invasive fungal infections.