The prostate in noncastrated male dogs typically experiences an increase in weight and size as they age, which can result in the development of prostatic disorders. Benign prostatic hyperplasia (BPH) is the most common prostate disorder in these dogs. The purpose of this study was to develop a model that could differentiate between dogs with normal prostate sizes and those with enlarged prostate sizes. To achieve this, the researchers evaluated prostate sizes and volumes estimated by B-mode ultrasound in healthy noncastrated dogs and dogs with BPH, considering factors such as weight, age, aorta diameter, and the presence of intraparenchymal cysts. Two hundred and sixty noncastrated male dogs of various breeds were used, with two hundred and thirty-three dogs in the healthy group and twenty-seven dogs in the BPH group. Data on breed, body weight, and age were collected for each dog, and B-mode ultrasound was performed to obtain prostate variables of length, width, and average height, as well as the presence/absence of intraparenchymal cysts and aorta diameter. All variables presented differences between groups except aorta diameter. All dogs with BPH were older than 6 years (p < 0.001), with a higher percentage of prostate cysts (p < 0.001) and larger prostate volumes than healthy dogs (81 ± 41 cm³ vs. 22 ± 15 cm³, p < 0.001). The outcomes of this research resulted in the creation of a model that can precisely (98.1%), sensitively (88.9%), and distinctly differentiate between healthy, noncastrated dogs and those with BPH by considering several factors, including body weight, age, aorta diameter, and the existence of intraparenchymal cysts.