Dogs exhibit patterns of health issues that vary by life stage. An understanding of disease incidence with respect to breed and age/life stage could be an important component of canine health management and welfare. This study aimed to describe the age-specific disease incidence of 3 small dog breeds that attended veterinary clinics in the Republic of Korea, based on data from electronic veterinary medical records (EVMRs). A total of 40,785 EVMRs from Maltese (n = 21,355), Miniature Poodle (n = 11,658) and Shih Tzu dogs (n = 7,772) were analyzed. Common health problems in 3 small dog breeds were 'diseases of the skin' and 'diseases of the ear,' respectively. Among dogs aged ≤ 3 years, 'preventive medicine' was the most common cause cited for veterinary clinic visits. Among dogs aged 4 to 8 years, the most frequent health problems were 'diseases of the skin.' Among dogs aged 9 to 13 years, 'heart diseases,' 'kidney diseases,' 'mammary gland tumor,' and 'neoplasia (unspecified)' were considerably more frequent, compared to the rates in dogs ≤3 years. Among dogs aged ≥ 14 years, 'heart diseases' and 'sneezing/cough' were the main health problems. In all breeds, the frequencies of 'diseases of circulatory system,' 'diseases of respiratory system,' 'diseases of the nervous system,' 'endocrine' and 'neoplasia' increased rapidly with aging. This surveillance could inform strategies for disease screening tests and management based on life stage in these dog breeds and enable more effective health management.