Introduction: Infertility is defined as the failure to conceive after one year of unprotected sexual intercourse. About genetic causes, both chromosomal abnormalities identifiable by karyotype analysis and gene mutations or submicroscopic deletions of the Y chromosomal azoospermia factor (AZF) region can disrupt spermatogenesis. Recently, the techniques of testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI) have made it possible to assist men with azoospermia or severe oligozoospermia to attain successful fertilization and pregnancies. Aims: To find out the frequency and type of abnormal karyotype and Y chromosome microdeletions in infertile males before ART. Study Design: A retrospective randomized analytical study. In this study, we enrolled 100 infertile male patients willing to go for ART. Results: In 100 infertile male patients, 72 were azoospermic and 28 were oligozoospermic. There was no significant difference in the mean ages of men with oligozoospermia(31.6) and azoospermia (33.1). The levels of FSH and LH in azoospermic males were significantly higher than those in the oligozoospermic males (P = 0.001). However, the levels of testosterone(P = 0.749) were not significantly different. Of 100 cases with male infertility, 89% had a normal karyotype (46, XY) and 11% had abnormal karyotype. Eight of the chromosomal abnormalities were gonosomal in patients with Klinefelter Syndrome and two were balanced reciprocal translocations involving autosomes. One of the translocations was 46,XY,t(3;7) (q24 ;q36) and the other was 46,XY,t(5;6) (q35 ;q21). All of those with Klinefelter Syndrome had azoospermia, but translocation carriers had oligospermia. 11.1% of azoospermic patients and 7.14% of oligozoospermic patients had chromosomal abnormalities. In the current study, Yq microdeletion was detected in only 1.38% of azoospermic cases, but not seen in other cases. Conclusions: The results of this study showed that infertile men had a higher prevalence of chromosomal alterations. Therefore, the higher incidence of the chromosomal anomalies among the infertile males strongly suggested karyotyping and counselling before ART.