A dual-chambered drug delivery device, comprising: a first chamber in which a medicament is stored; a dose setting member for setting a medicament dose, said dose setting member being rotatable to set the medicament dose by adjusting a position of a plunger rod connected to a second chamber, said dose setting member not being axially moveable, a longitudinal centerline of the dose setting member being parallel to a longitudinal centerline of the second chamber; the second chamber in fluid communication with said first chamber, said second chamber having a smaller cross sectional area than said first chamber, a longitudinal centerline of the first chamber being substantially parallel to and offset from the longitudinal centerline of the second chamber, the medicament dose being transferred to said second chamber from said first chamber by a force from a spring toward a stopper in the first chamber prior to injecting the medicament dose; and a needle communicating with said second chamber for injecting the medicament dose into an injection site when the plunger rod is depressed, wherein a first valve is open and a second valve is closed when a pressure inside the first chamber is greater than an opening pressure of the first valve and less than an opening pressure of the second valve to transfer the medicament dose from the first chamber to the second chamber when the second chamber is being filled, and the first valve is closed and the second valve is open when injection pressure is applied to the second chamber such that a pressure inside the second chamber exceeds the opening pressure of the second valve to block the medicament dose flowing from the second chamber to the first chamber when injecting the medicament dose from the second chamber through the needle and into the injection site; and the pressure in the first chamber is decoupled from a pressure in the second chamber via the first valve and the second valve. a first chamber in which a medicament is stored; a dose setting member for setting a medicament dose, said dose setting member being rotatable to set the medicament dose by adjusting a position of a plunger rod connected to a second chamber, said dose setting member not being axially moveable, a longitudinal centerline of the dose setting member being parallel to a longitudinal centerline of the second chamber; the second chamber in fluid communication with said first chamber, said second chamber having a smaller cross sectional area than said first chamber, a longitudinal centerline of the first chamber being substantially parallel to and offset from the longitudinal centerline of the second chamber, the medicament dose being transferred to said second chamber from said first chamber by a force from a spring toward a stopper in the first chamber prior to injecting the medicament dose; and a needle communicating with said second chamber for injecting the medicament dose into an injection site when the plunger rod is depressed, wherein a first valve is open and a second valve is closed when a pressure inside the first chamber is greater than an opening pressure of the first valve and less than an opening pressure of the second valve to transfer the medicament dose from the first chamber to the second chamber when the second chamber is being filled, and the first valve is closed and the second valve is open when injection pressure is applied to the second chamber such that a pressure inside the second chamber exceeds the opening pressure of the second valve to block the medicament dose flowing from the second chamber to the first chamber when injecting the medicament dose from the second chamber through the needle and into the injection site; and the pressure in the first chamber is decoupled from a pressure in the second chamber via the first valve and the second valve.