The purpose of this publication is the research of separate aspects of the history of the Crimean War (1853–1856) and Russian-Turkish War (1877–1878) and, in particular, the activities of the famous doctor N.I. Pirogov (1810–1881) concerning his care for the wounded and sick Russian soldiers during the heroic defense of Sevastopol and during the course of his treatment of the Grand Duke Nikolay Nikolaevich Romanov (Sr.) in the years of the Russian-Turkish War (1877–1878). The author used retrospective, narrative and biographic methods. The subject of this publication is very relevant because the history of the military conflicts of the second half of the 19^th century have not received detailed development in domestic historical science today. Nikolay Ivanovich Pirogov trained many famous doctors for medical work, one of whom was Alexander Leontyevich Obermiller. The famous scientist-surgeon N.I. Pirogov and his pupil, A.L. Obermiller, the graduate of the Imperial medical-surgical academy, worked together at first in a military and overland hospital, and then were participants in the heroic defense of Sevastopol, helping wounded and sick soldiers in the years of the Crimean War (1853–1856). They combined medical treatment with organizational work directed to improve the system of medical care during wartime, promoting the innovative methods offered by N.I. Pirogov. Sources of personal origin (N.I. Pirogov's published letters: «The Sevastopol letters and memoirs», letters to A.L. Obermiller), the central periodicals including weekly illustrations in the Vsemirnaya Illyustration magazine, publications of the N.I. Pirogov, and also publications of the doctors and scientists D.A. Balalykin, M.N. Kozovenko and S.I. Trikhina and other authors formed the basis of this research. Use of the epistolary heritage of Nikolay Ivanovich Pirogov as the most important source of this research allowed this writer to look at events of the Crimean War and Russian-Turkish War from a position of their contemporaries. The publication is of interest to historians and also to doctors and students of medical educational institutions.