This article deals with the Katta Langar manuscript, which is known as one of the earliest Qur'ān copies attributed to III. Caliph Uthman. The study consists of an introduction, a conclusion and two sections. The introduction section begins with the information that the Katta Langar Mushaf which is called by this name relative to the Katta Langar village of Uzbekistan, is in the library of the Tashkent Uzbekistan Muslims Administration. Only ninety-seven pages of the mushaf, which was lost for a period, have survived. Since twelve of these leaves appear again in Katta Langar, they are meant as the Katta Langar manuscripts. Therefore, this article not only aims to examine in detail all the extant leaves of the mushaf but also the twelve leaves, which are known today as the Katta Langar manuscripts. Although the research done so far has made it clear that this mushaf is not one of the copies of Uthman, the mushaf has been the subject of many studies. The first of the studies on the Katta Langar Mushaf was published by M.E. Masson, while the most detailed work belongs to Efim Rezvan. Existing studies on the mushaf are methodologically either a publication or a catalogue study. In this study, the Katta Langar copy was compared with the sources of the mushaf litera- ture and discussed more comprehensively. The first part of the article describes the historical adventure of Katta Langar leaves. The history is processed through two different narratives. As it is understood from both stories, a lot of struggles were fought for the protection of the mushaf against Russia's occupation policy and the negative attitude of the Uzbek Communist Party towards Islamic folk beliefs, but it was not pos- sible to preserve the mushaf as a whole. In the second part, the copy is examined in detail in terms of codicology and mushaf sciences such as orthography, qirā’āt, dabt and verse counting. Some assessments of Efim Rezvan are included under the title of codicology. The mushaf is inscribed on a quality deerskin parchment and is generally in good condition, although a few of its leaves are severely frayed. The font is late Hijazi. The Katta Langar Manuscripts, which are the subject of our research, were also sub- jected to carbon testing by Oxford University, and according to the result, the manuscripts were dated to the years 595-855 with a 95% probability. There are some interventions on the Langar leaves, which are understood to be done later. Other titles of the study are about mushaf sciences. A database was created by writing the words in Katta Langar leaves into the Microsoft Excel program, and the words categorized ac- cording to mushaf sciences were compared with the information in the literature and some an- cient masāhif published. The following information about the spelling of the mushaf stands out: The words with a long vowel (alif) in the orthographic sources are generally written with omission (hadif) in the Katta Langar Mushaf. In fact, it is noteworthy that 111 words that are not written with hadif in the sources are written with hadif. Regarding the imla features in Katta Langar manuscripts, it is seen that the orthography generally reflects the orthographic data in the mushaf literature. However, in places where the Katta Langar manuscript does not coincide with the mushaf literature, it has been determined that it has unity with the Cairo el-Maşhadu'l-Huseyni and Topkapı Qur'ān manuscripts, which are among the ancient masāhif attributed to Caliph Uth- man. Katta Langar leaves include four of the words that are reported to be different among Uthman masāhif. However, considering these data alone, it is not possible to talk about the exact overlap of the leaves with any city mushaf. When it comes to the determination of the preferred qirā’āt based on the diacritical marks in Katta Langar leaves, it is seen that the qirā’āt is compat- ible with ten canonical (sahih) qirā’āts. Dabt features of the Katta Langar copy draw attention. Although the i'cām points that separate similar letters from each other are placed regularly, they are neglected in some places. There are two different forms at the i'cām points, one linear and the other circular. It is thought that irreg- ular circular points were added later and the punctuation process continued at different times. Another difference in the i'cām is seen in the punctuation of the letter qaf (ق). The dabt system applied for the letter qaf in the Katta Langar leaves shows unity with the Cairo al-Maşhadu'l- Huseyni Mushaf and the Topkapi Mushaf. Moreover, additional alifs are seen in the manuscripts. It is obvious that these red alifs were added to the text by another hand, probably to make it easier to read. In the article, there is the title of verse counting after the dabt part. This title is discussed within the framework of the verses of the Surat al-Nisā, al-Māi’da and al-An'ām, which are available in the twelve-leaf copy. It is understood that the signs of the end of the verse in the Katta Langar leaves were placed in the process after the inscription of the copy. It is seen that it overlaps with Damascus and Basra in six of the seven places, which are subject to mushaf differences regarding the verse stops. In this case, it is highly probable that the copy is one of the masāhif of Damascus and Basra. When this information is taken into consideration with the imla and qirā’āt differences between the masāhif, the possibility that its belonging to Basra gains strength.