A 61-year-old woman underwent percutaneous transluminal coronary angioplasty (PTCA) to relieve stenosis of the left anterior descending coronary artery. During the procedure ophthalmoplegia with diplopia developed. The diagnosis was partial right third cranial nerve palsy and left fourth cranial nerve palsy. The cause is presumed to have been a microembolic infarct of the right peripheral third nerve coupled with either decompensation of pre-existing left superior oblique palsy or a separate microinfarct of the left trochlear nerve. Over 7 months of follow-up there was partial resolution of the ophthalmoplegia. Ophthalmoplegia during PTCA is rare, and to our knowledge this complication has not been reported in the ophthalmic literature.