Аннотация:The study concerns the Monte Carlo simulation of the optical coherence tomography (OCT) signal from blood and Intralipid layers. We show that in the case of the hematocrit values of 5 , 10, and 35%, the rear border of a 0.5-mm-thick blood layer is clearly distinguishable in the signal. The finding is in line with the fact that the least-scattering component gives a major contribution to the signal. In the case of Intralipid, the major contribution comes from the multiple- scattering component, and the signal from the rear border is not visible. The scattering properties of Intralipid, a highly scattering medium, can be ascertained fiom the slope of the downward slanting part of the signal. As it has been proved, the change of the detector radius strongly influences the shape of the signal. The larger the radius is, the larger is the contribution from multiple-scattered photons. On the contrary, the change of the numerical aperture (NA) of the detector does not change the shape of the signal, as the contributions from diversely scattered photons respond in a similar way. Hence, to optimize the determination of the properties of the media from the OCT signal slopes, a small detector radius and large NA should be used.