Moxidectin injectable solution (Cydectin NF 1% Fort Dodge)was administered subcutaneously (400 mcg/kg) in ten dogs naturally infected with Sarcoptes scabiei var. canis. Six of the dogs (60%) were males; seven (70%) were purebred. The dogs were between two and 108 months of age, with a weight range from 1.3 to 60 kg. Parasitic transmission to the owners was observed in 30% of the cases. After the diagnosis (skin scrapings, cutaneous lesions and signs) the moxidectin was administered twice in six dogs and three times in four dogs, every 15 days. The six dogs submitted to two doses did not show clinical improvement or have negative scrapings. Only two (50%) of the four dogs receiving three doses were cured. Cutaneous lesions (fistulated nodule, crusts and purulent exudate) were observed at the site of the moxidectin application in one (10%) dog. No systemic adverse effects were observed. These results disagree with the product monograph, the dosage of moxidectin administered in our cases did not prove successful, and, treatment might provoke important pharmacodermic adverse reactions.