Fecal examinations revealed that at least 10 of 21 (48%) captive red wolves (Canis rufus) and eight of 12 (67%) free-ranging red wolves were infected with intestinal parasites. No captive wolves and only one of seven reintroduced wolves had dirofilariasis. Ticks were collected from 10 of 21 (48%) captive wolves and nine of 12 (75%) free-ranging animals. Ivermectin administered at a dosage of 50 μg/Ag of estimated body weight every 30 to 60 days apparently prevented or ameliorated parasitism in red wolves.