The porphyrias comprise a clinically and genetically heterogeneous group of diseases mostly arising from a genetically determined dysfunction of specific enzymes along the pathway of heme biosynthesis. Based on the occurrence or absence of cutaneous symptoms and life-threatening acute neurological attacks, the different types of porphyrias can either be classified into cutaneous and non-cutaneous forms or acute and non-acute forms. Establishing an accurate diagnosis might be difficult for two reasons: i) the porphyrias can manifest with a broad but unspecific spectrum of clinical symptoms mimicking several other disorders, and ii) biochemical examination of urine, feces, and blood can reveal overlapping findings. Fortunately, however, the advances in the fields of molecular genetics during recent years have provided us with the possibility of overcoming these diagnostic pitfalls. Therefore, in controversial cases the correct diagnosis can finally be made using molecular biological techniques. Due to the various facets of the porphyrias, diagnosis and treatment should always imply a close interdisciplinary collaboration to counsel and help patients and their families most efficiently.