A blood sample collection device and procedure which employs a series of pre-evacuated rubber-capped vials for the drawing of successive samples. A hollow cylindrical carrier is used consisting of two cups which are integral base-to-base defining a main chamber and a mid-chamber. A soft rubber disc encloses the mid-chamber and defines an antechamber communicating with an intravenous needle. A piston carrying a double-ended auxiliary needle is slideable endwise in the mid-chamber. The antechamber is enclosed by transparent material such as plastic and is of such size as to admit only a trace of blood through the intravenous needle under venous pressure before the vial is connected, the blood in the antechamber serving as a visual telltale informing the user that the needle is in the lumen of the vein. The main chamber is laterally offset from the mid-chamber and antechamber, enabling the intravenous needle to be inserted at a shallow penetration angle notwithstanding the relatively large diameter of the main chamber and further insuring that the vial cap is penetrated in a random eccentric position. The vial is distinguished by use of an extensive rubber diaphragm held in place by screw-on cap which provides a reliable seal while permitting subsequent opening with only light manual twisting force.