Examination of the cranial nerves is an important part of complete neurological assessment of the patient. With the development of imaging techniques, there is an increased awareness of the possible anatomical variations and anomalies and although there is extensive data on the anatomical variations of some of the cranial nerves, cranial nerve I is relatively understudied. Although the data on olfactory nerve is not abundantly present, there are several types of developmental anomalies, which can be present as aplasia, hypoplasia, olfactory bulb ventricles, and duplication/triplication of the olfactory bulb. There are also several genetic conditions, in which olfactory system malformation are common and require further evaluation. The purpose of this review is to sum up the current data on the clinical anatomy, malformations of olfactory nerve, bulb, tract and associated conditions.