Introduction: An Atrial Septal Defect (ASD) is a persistent interatrial communication, accounts for approximately 6–10% of congenital defects. ASD types include Ostium Secundum, Ostium Primum, Sinus Venosus, and Coronary sinus defects. Small ASDs may not have significant clinical consequences, while a large defect may lead to life threatening symptoms. The objective of the study is to estimate the prevalence of ASD in the hearts of adult human cadavers.

Materials and Methods: The present study was conducted on a total of 25 Hearts obtained from cadavers allotted to the undergraduate medical students and preserved specimens from the Department of Anatomy.

Results: The presence of Ostiumsecundum ASD was seen in 1 out of 25 specimens (4%). It was an elliptical opening measuring 10×8 mm.

Conclusion: ASDs are associated with the risk of Stroke, Transient Ischaemic Attack, and Paradoxical Embolism. The Anatomical knowledge of the position of the ASD and it's morphometric knowledge enables it to differentiate between various Septal Defects. ASDs are usually closed by surgical intervention or by Percutaneous Transcatheter Closure.

Keywords: Foramen ovale; Atrial septal defect; Septum secundum; Cadaveric study.