ABSTRACT. Y chromosome microdeletions can cause male infertility and are classified as natural transmission and de novo mutations. To examine the source of these deletions in Chinese men and to provide a theoretical and laboratory basis for genetic counseling, patients from Northeast China with primary male infertility (N = 22) and their fathers were investigated. Karyotype analysis was performed on peripheral blood lymphocytes using standard G-banding. Multiplex polymerase chain reaction amplification using 18 specific sequence-tagged sites was selected to detect Y chromosome microdeletions. De novo mutations were observed in 17 father-son pairs, leading to a mutation rate of 77.27% (17/22), while the vertical transmission of Yq AZFc microdeletions was detected in 5 cases of the families investigated (29.41%, 5/17). There were no statistically significant differences between vertically transmitted and de novo mutations in men with AZFc deletions regarding age, testicular volume, and reproductive hormone 1933 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (1): 1932-1941 (2015 Y chromosome microdeletions in infertile Chinese men levels. Most Y chromosome microdeletions in men from Northeast China are the result of de novo mutations via natural conception, and men with Yq AZFc deletions showed no clear differences between vertical transmission and de novo mutations.