A catheter insertion device is provided that includes an insertion needle that is retractable into the device after use to prevent exposure to the contaminated needle. The needle retainer releasably retains the needle in an extended position against the bias of the biasing element. When the catheter is removed from the insertion device, the needle retainer automatically releases the needle, which is propelled rearwardly into the device.A device for inserting a guide wire into a patient is also provided. The device includes an insertion needle that is retractable into the housing of the device after use. A needle retainer releasably retains the needle in an extended position against the bias of the biasing element. After the guide wire is inserted into the patient, the needle retainer allows the needle to be released, so that the needle is retracted into the device.