It has been proposed that apolipoprotein J (apo J) and paraoxonase-1 (PON1) correlate with the extent and severity of ischemic heart disease (IHD). This article compares apo J and PON1 serum concentrations, PON1 activity, and the apo J/PON1 ratio in 138 IHD patients (64 statins users and 74 statin nonusers) referred for angiography and possible percutaneous coronary intervention. The effect of statin treatment on apo J and PON1 concentrations, PON1 activity, and the degree of coronary artery stenosis were evaluated. In both groups, apo J levels were increased, whereas PON1 concentration and activity decreased. IHD patients on statins had significantly lower apo J concentration and higher PON1 concentration and activity. Patients on statins had less coronary artery stenosis. High apo J levels, low PON1 levels, low PON1 activity, and a high apo J/PON1 ratio were associated with IHD. Statin treatment reverses these changes, probably by multiple beneficial actions.