Bismuth–antimony alloys that form a continuous series of solid solutions are promising thermoelectric materials. Scientists from the University of Massachusetts [1] have theoretically predicted a significant increase in the thermoelectric efficiency in low-dimensional objects based on these materials (up to 40 nm.). This increase is attributed to the alignment of the edges of ten subbands with respect to energy and an increase in the density of states due to the size effect. Therefore, examination of the effect of sample thickness on the kinetic coefficients of Bi1–xSbx film single crystals is an urgent problem. Bismuth–antimony film single crystals were grown by zone melting under a protective layer (KBr; CsI) [2]. All the samples exhibited the same feature: the C3 axis was perpendicular to the substrate plane. The thicknesses were varied in a range of 0.3–2.0 μm. Temperature dependences of the resistance, thermoelectric power, and power factor (α2σ) in a temperature range of 77–300 K were studied.  According to the derived ) α (T ) and ρ (T) dependences, temperature dependences of the power factor for film single crystals of all compositions were calculated and plotted. The highest power factor value was obtained for the Bi0.88Sb0.12 sample with a diameter of 1.4 μm; it was 1.1 x10–4 W/cm K2 at T = 120 K. The broad maximum formed near 120 K is shifted to higher temperatures with decreasing thickness. This behavior is similar to that of thin wires. The calculated Z value was 3.67 x10–3 K–1. The thermoelectric dependence was calculated according to the expression Z = α2σ/χ, where χ is the thermal conductivity and ZT ~ 0.44, which is comparable to the values obtained for thin wires and bulk samples.