The avascular necrosis of the femoral head is a developmental disease, more commonly observed in young dog, related to an ischemic necrosis. The aim of this retrospective study was to evaluate a population of dogs with avascular necrosis of the femoral head for characterize it and classify the radiographic patterns of the bone lesions. From 35 dogs (n = 37 hind limbs) evaluated in a period of nine years, 54.3% had aged from 6 to 11 month, 42.9% aged from 12 and 36 months, and 2.9% aged above 36 months. Considering the range of body weight, 14.9% of the dogs had between 1.4 and 2.5 kg, 62.8% between 2.6 and 4.9 kg, and 22.8% between 5 and 7.5 kg, with an overall average of 4.33 kg. Female dogs were 62.9% of the cases. The dog breeds were Pinscher (n = 8), Yorkshire (n = 7), Poodle (n = 5), Lhasa Apso (n = 3), Pug (n = 2), and four other breeds with 1 animal each. Six dogs were crossbreed. Most of the lesions were unilateral. Lameness was observed in 97.1% of the cases, 28.5% showed non-weightbearing on the affected limb, and 2.9% did not show signs of lameness. Based on radiographic staging, 5.4% were grade 1 (n = 2), 37.8% grade 2 (n = 14), 8.1% grade 3 (n = 3), 16.2% grade 4 (n = 6), and 32.4% grade 5 (n = 12). In conclusion, the population of the present study was composed by small-sized dogs, mean body weight of 4.3 kg, mostly presenting with unilateral lesions, classified especially as grades 2 and 5.