Background: Cryptorchidism is the most common congenital abnormality affecting male reproductive development in dogs. Castration is generally recommended for affected individuals, and many cases are identified incidentally during elective procedures. A better understanding of the epidemiology and clinical characteristics of cryptorchidism may enhance awareness among veterinarians and dog owners, thereby contributing to improved surgical management and postoperative care. Methods: Clinical data were retrospectively collected from dogs diagnosed with cryptorchidism between 2018 and 2025. Cryptorchidism was classified according to the anatomical location and laterality of the undescended testis. Breed-related associations were evaluated by comparing distribution patterns between purebred and mixed-breed dogs using Fisher’s exact test and odds ratios analyses. Results: Among 618 dogs undergoing castration, 80 were diagnosed with cryptorchidism (12.94%). Right-sided unilateral cryptorchidism was the most common presentation (n = 55, 8.90%), followed by left-sided unilateral cryptorchidism (n = 17, 2.75%), and bilateral cryptorchidism was the least frequent (n = 8, 1.29%). Undescended testes were more frequently located in the inguinal region (n = 53, 66.25%) than in the abdominal cavity (n = 27, 33.75%). No statistically significant breed-specific differences in anatomical location were detected when compared with mixed-breed dogs. Conclusions: This study characterizes dog cryptorchidism based on anatomical location and laterality, providing baseline clinical data on breed-related distribution patterns that may support future studies of clinical decision-making.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
    Study population
    Statistical analysis
RESULTS
    Clinical characteristics of cryptorchidism
    Breeds distribution
    Correlation of distribution patterns by breed
DISCUSSION
CONCLUSION
REFERENCES

• Young-Bum Son(Department of Obstetrics, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Korea) Corresponding author
• Sang-Yun Lee(Department of Obstetrics, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Korea)
• Minsu Baek(Department of Obstetrics, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Korea, Forev Animal Medical Center, Dongducheon 11362, Korea)
• Won-Jae Lee(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea)
• Dong-Ju Park(Division of Animal Bioscience and Integrated Biotechnology, Institute of Agricultural and Life Science, Gyeongsang National University, Jinju 52828, Korea)