The determination of the differences by the comparison of Hadīth books, i.e. the zawāid studies, constitutes the first step of endeavors for gathering all hadīth collections together by purifying from the repetitions. In this study written among the scope of zawāid literature that has lost its outstanding period caught in the 8th and 9th centuries, but regained its vigorousness by today's academic studies, Tirmidhi's Cāmi' has been accepted as the basis and the other five books forming the Kutub al-Sittah have been used as the criterion book. The number of zawāid hadīths existing in Cāmi' but not existing in Sahīhayn and three Sunan is 1280. While the 96% (1231 narratives) of them were marfū' hadīths, 49 narratives (4%) were mawkūf or maktū' hadiths. Tirmidhi has judged on 1084 (i.e. 88%) of the 1231 marfū' narratives and made no evaluations on the 12% of them (147 hadīths). In the table obtained by the tahrīc and reviews, the Tirmidhi zāwaid was particularly formed by the hadīths of garīb (22%), hasen-garīb (22%) and hasen-sahīh (21%). When this situation was compared with the whole Cāmi', the average reliability was less than that of Cāmi'. [ABSTRACT FROM AUTHOR]