There is no difference between MBA (Masters in Business Administration) & PGDM (Post Graduation Diploma in Management). These are more or less same management degree courses offered under the different tag by different institutions.

As per the law in India, only a university can offer courses like B.E. B.Tech and MBA. At the end of MBA students receives a degree whereas after a PGP/PGDM course students receives a diploma. If you are wondering that MBA is better than let me remind you the best colleges for management in India like IIMs, XLRi Jamshedpur, S.P. Jain offers a PGDM/PGP course. Most of these institutes are autonomous bodies (not affiliated to any University) and conducts their own management course.

MBA courses focus more on theoretical and technical aspects of management rather than adopting a practical approach. PGP or PGDM courses have an industrial orientation and focus on skills based on market requirements.

It has been observed that most MBA courses have lower tuition fees as compared to PGP or PGDM courses. This may be so because mostly government approved universities offer MBA degrees. These universities receive financial aid and grants from the government, making the degree cheaper for the student (FMS which falls under Delhi University is best in terms of ROI with INR 20K fees for 2 years and an average package of INR 20.5 lakhs per annum). In case of a PGP or PGDM degree, students have to bear the cost of the entire programme. However, this is not an ironclad rule. There are MBA degrees which charge high tuition fees (such as IIFT).

For your information, there is no separate exam conducted for MBA/PGDM/PGP course because all depends on college to give admission on which type of exam marks and offer a which type of degree.