Abstract: A utility knife comprises a hollow casing formed by a pair of elongated members pivotally mounted one to the other at one end of the casing. A blade passage is provided at another end of the casing. The elongated members are adapted for movement in substantially parallel planes between aligned closed functional and open diverging positions. The casing is provided with a mechanism adapted to carry and selectively position a blade. The utility knife further comprises a locking member pivotally mounted to one of the elongated members and adapted in a closed position thereof to secure the elongated members in their aligned closed position.