This study investigated acoustic properties of the four-way contrast in Russian voiceless sibilant fricatives (/s
/). Words with these consonants, occurring in a variety of phonetic contexts, were elicited from 10 Russian native speakers. Measurements were made of duration, centre of gravity (COG) and intensity of fricative noise, as well as of formants F1–F3 during the following vowel. The results revealed that the anterior vs. posterior contrast was clearly distinguished by COG throughout the frication period, and to a lesser degree by noise intensity. The palatalized vs. non-palatalized contrast was distinguished by F1 and (especially) F2 at the onset, the midpoint, and, in some cases, at the offset of the following vowel. The four-way contrast was thus well categorized by a combination of COG and F2–F1 differences. Fricative duration only marginally distinguished /ʃj/, commonly described as geminate, from the other consonants. Clear durational differences, however, were observed for the same consonants in different positional and stress contexts. Overall, the results of the study provide a systematic documentation of the typologically uncommon fricative contrast, while also shedding light on some facts of synchronic patterning and historical development of the fricative system of Russian.