The results of experimental studies of the absorption spectra of pure NH3 at room temperature in the range 6611.6 - 6613.5 cm-1 and pressure range (up to 0.01 atm.) are presented. The measurements were carried out at the Department of Diode Laser Spectroscopy of the Institute of General Physics on a high-sensitivity high-resolution diode laser spectrometer with a signal-to-noise ratio of ~ 1400. The spectra were analyzed using a Voigt contour. The results of reconstructing the parameters of spectral absorption lines are presented: the positions of centers, intensities, coefficients of collisional self-broadening and shifts. A comparison was made with the parameters of the HITRAN database. A ~ 2-fold difference in intensities was found. Ammonia is one of the most common chemicals in human activity, is a waste product of living organisms and one of the most important products of the chemical industry. Ammonia is used to produce nitric acid, nitrogen fertilizers, explosives, etc. Ammonia is toxic and, along with such molecules as CO, NO, CH4, 13CO2, is a biomarker molecule1,4. These circumstances lead to the need to ensure continuous monitoring of ammonia and the development of reliable, low-cost measuring instruments in the environment, food industry and medicine. Currently one of the most highly sensitive and highly selective modern methods of gas analysis is diode laser spectroscopy. However, the realization of the advantages of this method is largely determined by the quality of the spectral data basis used, represented by the HITRAN database. One of the promising spectral ranges for monitoring NH3 is the region 6604 - 6613 cm-1 2. And another paper presents the results of experimental studies and analysis of the absorption spectra of pure NH3 in the range 6547 - 6552 cm-1 at room temperature and pressure range 0-0.04 atm 3.