Which year is the Shmitta year? Here is the Gemorrah in tractate Taanis 29a. The subject is the destruction of the second Temple on Tisha B'av and gives the exact moment of the destruction: The gemorrah tells us the story of the destruction of the second Temple, that it happened on Tisha B'av after Shabbos and after the shmitta year. Rashi tells us that after shmitta means in the eighth year. Of course, shmitta is in the seventh year and so after that comes the eighth year. You might wonder why Rashi has to comment at all. The Rambam saw the gemorrah differently. His opinion is that since the New Year starts in Tishrei, less than two months after the destruction of the Temple, so "after shmitta" written here means "at the end of shmitta". (Rambam Hilchos Shmitta veyovel ch. 10). In other words the Temple was destroyed during the course of the shmitta year. And there is a very good reason to want to know during which year of the seven-year cycle the Temple was destroyed: This is the only place in Chazal that an historical event was related to the seven-year cycle. Once we know during which of the seven years it happened we simple continue counting seven-year cycles up to the present day. Then we will know which year is shmitta in our generation. If you read the above chapter in the Rambam you will note that he brings down two opinions when Shmitta occurs in his day. The first is according to the Rambam's own opinion that the Temple was destroyed during shmitta. The second opinion he brings down as the opinion of the Geonim and notes that in the land of Israel this is what is actually followed. The subject is quite complicated. Somebody interested is invited to look at the commentators on the Rambam and also those of the Tur and Shulchan Aruch (Hoshen Mishpat ch. 67). The Rama in Shulchan Aruch ruled that all Jews need to know when is shmitta because of the law of cancelling loans, which happens the final hours of the shmitta year. In Israel today we follow the cycle of the Geonim mentioned above, and the last Shmitta was in the year 5761, which will began September 30, 2000. And the next one in 2007