Most similar in habitus to Theretra rhesus and Theretra acuta but can be distinguished from these species by the lack of several pattern features, such as the narrow yellow stripes on the tegulae, a large, triangular black basal patch on the forewing underside, and a clear serrate medial band on the hindwing underside. Additionally, Theretra makhrovi has clear pink shade on the underside of both wings that is absent in the two other species and has narrower and longer wings.
In addition, and not noted in the original description, on the forewing upperside of Theretra makhrovi, postmedial band 3 is displaced distally to fuse with postmedial band 4 for most of its length, separating above vein M2. This makes it appear as if there is only a single postmedial line in the pale area between the two strongest postmedial bands, 1 and 4. In Theretra acuta, Theretra rhesus and Theretra insularis, there are two clear postmedial lines, 2 and 3, within this pale band. All of these features need to be confirmed in more specimens than the singleton holotype.
Male genitalia: Stated in the original description to be distinguishable from similar species by the (undescribed) shape of the harpe and the narrower valve, but these purported differences are unlikely to hold as both structures are quite individually variable within species of the larger "grey" Theretra.