An intravenous catheter assembly comprising: a catheter tube; a catheter hub having a distal end and a proximal end, wherein the distal end is joined to the catheter tube and the proximal end defines a housing having inner space; a needle extending through the catheter hub and the catheter tube and defining an axial direction, wherein the needle has opposite proximal and distal ends, the distal end forming a needle tip; a port extending outwardly in a direction perpendicular to the axial direction from a sidewall of the catheter hub; a needle hub attached to the proximal end of the needle having a housing; a needle guard slidably arranged on the needle and an upper end of the needle guard is securely retained in the housing of the catheter hub exposing the lower end of the needle guard and wherein in the ready to use position, the catheter hub is securely retained in an inner space of the needle hub, such that the entire lower end of the needle guard is located in the inner space of the needle hub, characterized in that the needle guard includes a base portion and first and second arms extending from the base portion, wherein the first arm is deflected radially outwards by the needle against a restoring force when the needle is in its ready position whereby the needle guard is brought into retaining contact with the catheter hub by retaining means for retaining the needle guard in the catheter housing as long as the first arm is in its deflected state and wherein the retaining means include a first disc-like retaining protrusion provided on the first arm and a retaining depression formed in an inner surface of the catheter hub and adapted to receive the retaining protrusion. a catheter tube; a catheter hub having a distal end and a proximal end, wherein the distal end is joined to the catheter tube and the proximal end defines a housing having inner space; a needle extending through the catheter hub and the catheter tube and defining an axial direction, wherein the needle has opposite proximal and distal ends, the distal end forming a needle tip; a port extending outwardly in a direction perpendicular to the axial direction from a sidewall of the catheter hub; a needle hub attached to the proximal end of the needle having a housing; a needle guard slidably arranged on the needle and an upper end of the needle guard is securely retained in the housing of the catheter hub exposing the lower end of the needle guard and wherein in the ready to use position, the catheter hub is securely retained in an inner space of the needle hub, such that the entire lower end of the needle guard is located in the inner space of the needle hub, characterized in that the needle guard includes a base portion and first and second arms extending from the base portion, wherein the first arm is deflected radially outwards by the needle against a restoring force when the needle is in its ready position whereby the needle guard is brought into retaining contact with the catheter hub by retaining means for retaining the needle guard in the catheter housing as long as the first arm is in its deflected state and wherein the retaining means include a first disc-like retaining protrusion provided on the first arm and a retaining depression formed in an inner surface of the catheter hub and adapted to receive the retaining protrusion.