The present study was carried out on 224 dogs, with various signs of prostatic diseases. Different means of diagnosis of prostatic diseases in dogs with special regard to uitrasonography were performed. Diagnosis of prostatic diseases is based mainly in our presented work on ultrasono¬graphy and different prostatic diseases have been diagnosed including; benign prostatic hyperplasia, intraprostatic cysts (simple solitary, multiple and complicated), paraprostatic cysts, prostatitis (chronic interstitial and chronic suppurative), prostatic abscess (simple solitary, simple multifocal, multilobulated) and prostatic neoplasia. By this means the detailed description of ultrasonographic pictures of all these diseases have been documented with special reference to differential diagnostic points of view. The prostatic dimensions (L x T x B), parenchymal echogenicity (anechoic, hypoechoic and hyperechoic), presence or absence of intrapa¬renchymal cavities, acoustic shadow and distant enhancement, are the guide lines used for differential diagnoses of these diseases.