Introduction: Many case reports have described anatomical variants of the pectoralis muscle. However, there has been little information published regarding this topic. So, the present study attempts to examine the different types of variations of pectoralis major muscle in terms of its origin, insertion, and nerve supply. Methods: The research was carried out on 40 cadavers ( 32 male and 8 female) in the department of anatomy, B.J .G. M. College, Pune from 2013 to 2014. Results: During dissection, out of the 40 cadavers, in a male cadaver left pectoralis major muscle variation was observed. Origin of the pectoralis major was found to be normal. However, a tendinous slip arising from deep lamina of pectoralis major muscle near its insertion on lateral lip of intertubercular sulcus of humerus was found. This tendinous slip along its course, was found to cross the musculocutaneous nerve, median nerve, brachial vessels, and ulnar nerve from lateral to medial side and blend with medial intermuscular septum 2.5 cm above the medial epicondyle of humerus. Then, it was found to be inserted on the medial epicondyle of the humerus. In all specimens of pectoralis major, the innervation by medial and lateral pectoral nerves was observed to be constant. No other variations were noted in the specimens of pectoralis major muscle. Conclusion: Anatomical knowledge of variations of Pectoralis Major muscle is important for plastic surgeons during reconstructive surgeries, neurologists, radiologists, orthopaedic surgeons, physiotherapists