Number theory is an ancient subject, but we still cannot answer many simplest and most natural questions about the integers. Some old problems have been solved, but more arise. All the research for these ancient or new problems implicated and is still promoting the development of number theory and mathematics. The main objective of the “Gandhi’s Contributions to Theory of Numbers Vol – I” to serve the latest papers of Prof. Gandhi to research scholars, especially Number Theory community to know the current research by a single author. In general, we will find few (or nil) papers in (general) mathematics journals, if the journal is not intended for Theory of Numbers. However, here one can get all the latest articles on Theory of Numbers of a single author (Prof. Gandhi), which he prepared and published during 2011-12. This Vol - I, contains 16 articles involving the CRT, functions, or problems and conjectures like Gold Bach, Twin-Primes, Cryptography and one on Mathematical Physics. All these papers are original contribution from Prof. Gandhi, BITS-VIZAG. Also, there is a second volume of this series, which will be appearing in the near future as 'Vol – II'.