An electrochemical dopamine (DA) sensor has been fabricated by modifying a glassy carbon electrode (GCE) with ruthenium disulfide (RuS2) nanoparticles (NPs). FESEM and TEM micrographs show the NPs to have an average size of ~45 nm. XRD, Raman and EDS, in turn, confirm the successful formation of cubic phased RuS2 NPs. The modified GCE displays has attractive features of merit that include (a) an ultra-low detection limit (73.8 nM), (b) fast response time (< 4 s), (c) a low oxidation potential (0.25 V vs. Ag|AgCl), (d) excellent reproducibility and stability, (e) an electrochemical sensitivity of 18.4 μA μM−1 cm−2 and 1.8 μA.μM−1.cm−2 in the linear ranges from 0.1–10 μM of DA (R2 = 0.97) and 10–80 μM of DA (R2 = 0.99), respectively. The sensor exhibits excellent specificity over potential interferents like ascorbic acid, glucose and uric acid. The superior performance of the sensor is attributed to its high electrical conductivity, large electro-active surface, and large numbers of exposed catalytically active sites resulting from the presence of unreacted sulfur atoms. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature.