In spite of strange claim of Mazicioglu [1] about Turkish origin of Avicenna, he was obviously a Persian scientist. Although it is too obvious, I present some evidence to clarify the subject. When we talk about Avicenna, we should look at the geographical situation of region 1000 years ago (Old Persia). It was too different from the current status. Avicenna was born in Afshaneh, the small city near the Balkh. It was one of the cities located in Khorasan Province of Iran in those days (Fig. 1). This region was separated from Iran by Russians only less than 200 years ago. Also, Afghanistan was independent from Iran in the same time. Most of the eastern parts of Afghanistan (like Herat) were a part of Khorasan Province in those days [2]. Turkish nationality originated from Turk tribes who lived in the east of Persia before Islam (before 637 AD). They tried to attack the western civilized territories, but Sassanids (Persian dynasty, 224–637 AD) stopped them at the eastern borders of Persia. Bahrām Chobin, the Persian commander defeated the Turkish army in the last years of the sixth century AD [3]. But, after Islam, Turkish territories were captured by Muslims and they became Muslim. Centuries later, some of them immigrated to the east with political and military powers and located in Anatolia (current Turkey) and changed the nationality of the region. On the other hand, Ozbaks, as wilderness tribes immigrated to this region under the command of Muhammad Shaybani Khan in the late sixteenth century AD (six centuries after Avicenna) [4]. The people who lived there were Persians. Parthians, one of three most important branches of ancient Persians is one of these examples. They ruled Persia from 247 BC to 224 AD [5]. Bukhara in Avicenna’s time was the capital of Samainds, the Iranian dynasty. Also, Khawrazm (Khawrazm) and Samarkand two main cities in this era were the capitals of Iran during Khwarazmian dynasty (1077–1231 AD), a bit after Avicenna’s death [6]. Avicenna had no Turkish manuscript. He wrote his scientific works in Arabic (as lingua franca of that time) and Persian (as his native language). At the Islamic time, transfers of cultural and scientific issues between nations were too high. We can find too many herbs and natural remedies called in Greek, Indian and other languages in most of the manuscripts written by Muslim scientists in that era. Regarding this, it is not a testimony for their nationality. In addition, the Mazicioglu letter contains historical errors. Avicenna did not just spend some of his last days in Hamadan; but he spent most of his life in various Persian cities like Gorgan, Ghazvin, Isfahan and Hamadan. He was the minister of Shams al-Dawla, the Buyid dynasty Ruler of Hamadan. He wrote his main books Shafa and canon of medicine in this city [7]. Also, I should talk about a very strange claim of the author about transferring initial medical sciences from Egypt to Greece in ancient time and then, developing it by Turkish scientists in the Islamic era. As it is known, humoral theory of medicine was presented by Indians and This reply refers to the comment available at doi:10.1007/s00404-015-3757-3.